Google Visualization API Reference

This page lists the objects exposed by the Google Visualization API, and the standard methods exposed by all visualizations.

Note: The Google Visualization API namespace is google.visualization.*

DataTable Class

Represents a two-dimensional, mutable table of values. To make a read-only copy of a DataTable (optionally filtered to show specific values, rows, or columns), create a DataView.

Each column is assigned a data type, plus several optional properties including an ID, label, and pattern string.

In addition, you can assign custom properties (name/value pairs) to any cell, row, column, or the entire table. Some visualizations support specific custom properties; for example the Table visualization supports a cell property called 'style', which lets you assign an inline CSS style string to the rendered table cell. A visualization should describe in its documentation any custom properties that it supports.

See also: QueryResponse.getDataTable

Constructor

Syntax

DataTable(opt_data, opt_version)

opt_data

[Optional] Data used to initialize the table. This can either be the JSON returned by calling DataTable.toJSON() on a populated table, or a JavaScript object containing data used to initialize the table. The structure of the JavaScript literal object is described here. If this parameter is not supplied, a new, empty data table will be returned.

opt_version

[Optional] A numeric value specifying the version of the wire protocol used. This is only used by Chart Tools Datasource implementors. The current version is 0.6.

Details

The DataTable object is used to hold the data passed into a visualization. A DataTable is a basic two-dimensional table. All data in each column must have the same data type. Each column has a descriptor that includes its data type, a label for that column (which might be displayed by a visualization), and an ID, which can be used to refer to a specific column (as an alternative to using column indexes). The DataTable object also supports a map of arbitrary properties assigned to a specific value, a row, a column, or the whole DataTable. Visualizations can use these to support additional features; for example, the Table visualization uses custom properties to let you assign arbitrary class names or styles to individual cells.

Each cell in the table holds a value. Cells can have a null value, or a value of the type specified by its column. Cells optionally can take a "formatted" version of the data; this is a string version of the data, formatted for display by a visualization. A visualization can (but is not required to) use the formatted version for display, but will always use the data itself for any sorting or calculations that it makes (such as determining where on a graph to place a point). An example might be assigning the values "low" "medium", and "high" as formatted values to numeric cell values of 1, 2, and 3.

To add data rows after calling the constructor, you can call either addRow() for a single row, or addRows() for multiple rows. You can add columns as well by calling the addColumn() methods. There are removal methods for rows and columns as well, but rather than removing rows or columns, consider creating a DataView that is a selective view of the DataTable.

If you change values in a DataTable after it is passed into a visualization's draw() method, the changes will not immediately change the chart. You must call draw() again to reflect any changes.

Note: Google Charts does not perform any validation on datatables. (If it did, charts would be slower to render.) If you provide a number where your column is expecting a string, or vice versa, Google Charts will do its level best to interpret the value in a way that makes sense, but will not flag mistakes.

The following example demonstrates instantiating and populating a DataTable with a literal string, with the same data as shown in the JavaScript example above:

var dt = new google.visualization.DataTable({
    cols: [{id: 'task', label: 'Task', type: 'string'},
           {id: 'hours', label: 'Hours per Day', type: 'number'}],
    rows: [{c:[{v: 'Work'}, {v: 11}]},
           {c:[{v: 'Eat'}, {v: 2}]},
           {c:[{v: 'Commute'}, {v: 2}]},
           {c:[{v: 'Watch TV'}, {v:2}]},
           {c:[{v: 'Sleep'}, {v:7, f:'7.000'}]}]
    }, 0.6);

The following example creates a new, empty DataTable and then populates it manually with the same data as above:

var data = new google.visualization.DataTable();
data.addColumn('string', 'Task');
data.addColumn('number', 'Hours per Day');
data.addRows([
  ['Work', 11],
  ['Eat', 2],
  ['Commute', 2],
  ['Watch TV', 2],
  ['Sleep', {v:7, f:'7.000'}]
]);

Methods

data.addRow();  // Add an empty row
data.addRow(['Hermione', new Date(1999,0,1)]); // Add a row with a string and a date value.

// Add a row with two cells, the second with a formatted value.
data.addRow(['Hermione', {v: new Date(1999,0,1),
                          f: 'January First, Nineteen ninety-nine'}
]);

data.addRow(['Col1Val', null, 'Col3Val']); // Second column is undefined.
data.addRow(['Col1Val', , 'Col3Val']);     // Same as previous.

data.addRows([
  ['Ivan', new Date(1977,2,28)],
  ['Igor', new Date(1962,7,5)],
  ['Felix', new Date(1983,11,17)],
  ['Bob', null] // No date set for Bob.
]);

var rowInds = data.getSortedRows([{column: 2}]);
for (var i = 0; i < rowInds.length; i++) {
  var v = data.getValue(rowInds[i], 2);
}

{"cols":[{"id":"Col1","label":"","type":"date"}],
 "rows":[
   {"c":[{"v":"a"},{"v":"Date(2010,10,6)"}]},
   {"c":[{"v":"b"},{"v":"Date(2010,10,7)"}]}
 ]
}

Format of the Constructor's JavaScript Literal data Parameter

You can initialize a DataTable by passing a JavaScript string literal object into the data parameter. We'll call this object the data object. You can code this object by hand, according to the description below, or you can use a helper Python library if you know how to use Python, and your site can use it. However, if you want to construct the object by hand, this section will describe the syntax.

First, let's show an example of a simple JavaScript object describing a table with three rows and three columns (String, Number, and Date types):

{
  cols: [{id: 'A', label: 'NEW A', type: 'string'},
         {id: 'B', label: 'B-label', type: 'number'},
         {id: 'C', label: 'C-label', type: 'date'}
  ],
  rows: [{c:[{v: 'a'},
             {v: 1.0, f: 'One'},
             {v: new Date(2008, 1, 28, 0, 31, 26), f: '2/28/08 12:31 AM'}
        ]},
         {c:[{v: 'b'},
             {v: 2.0, f: 'Two'},
             {v: new Date(2008, 2, 30, 0, 31, 26), f: '3/30/08 12:31 AM'}
        ]},
         {c:[{v: 'c'},
             {v: 3.0, f: 'Three'},
             {v: new Date(2008, 3, 30, 0, 31, 26), f: '4/30/08 12:31 AM'}
        ]}
  ],
  p: {foo: 'hello', bar: 'world!'}
}

Now let's describe the syntax:

The data object consists of two required top-level properties, cols and rows, and an optional p property that is a map of arbitrary values.

Note: All property names and string constants shown are case-sensitive. Also, properties described as taking a string value should have their value enclosed in quotation marks. For example, if you wish to specify the type property as being number, it would be expressed like this: type: 'number' but the value itself, as numeric, would be expressed like this: v: 42

cols Property

cols is an array of objects describing the ID and type of each column. Each property is an object with the following properties (case-sensitive):

• type [Required] Data type of the data in the column. Supports the following string values (examples include the v: property, described later):
  • 'boolean' - JavaScript boolean value ('true' or 'false'). Example value: v:'true'
  • 'number' - JavaScript number value. Example values: v:7 , v:3.14, v:-55
  • 'string' - JavaScript string value. Example value: v:'hello'
  • 'date' - JavaScript Date object (zero-based month), with the time truncated. Example value: v:new Date(2008, 0, 15)
  • 'datetime' - JavaScript Date object including the time. Example value: v:new Date(2008, 0, 15, 14, 30, 45)
  • 'timeofday' - Array of three numbers and an optional fourth, representing hour (0 indicates midnight), minute, second, and optional millisecond. Example values: v:[8, 15, 0], v: [6, 12, 1, 144]
• id [Optional] String ID of the column. Must be unique in the table. Use basic alphanumeric characters, so the host page does not require fancy escapes to access the column in JavaScript. Be careful not to choose a JavaScript keyword. Example: id:'col_1'
• label [Optional] String value that some visualizations display for this column. Example: label:'Height'
• pattern [Optional] String pattern that was used by a data source to format numeric, date, or time column values. This is for reference only; you probably won't need to read the pattern, and it isn't required to exist. The Google Visualization client does not use this value (it reads the cell's formatted value). If the DataTable has come from a data source in response to a query with a format clause, the pattern you specified in that clause will probably be returned in this value. The recommended pattern standards are the ICU DecimalFormat and SimpleDateFormat .
• p [Optional] An object that is a map of custom values applied to the cell. These values can be of any JavaScript type. If your visualization supports any cell-level properties, it will describe them; otherwise, this property will be ignored. Example: p:{style: 'border: 1px solid green;'}.

cols Example

cols: [{id: 'A', label: 'NEW A', type: 'string'},
       {id: 'B', label: 'B-label', type: 'number'},
       {id: 'C', label: 'C-label', type: 'date'}]

rows Property

The rows property holds an array of row objects.

Each row object has one required property called c, which is an array of cells in that row. It also has an optional p property that defines a map of arbitrary custom values to assign to the whole row. If your visualization supports any row-level properties it will describe them; otherwise, this property will be ignored.

Cell Objects

Each cell in the table is described by an object with the following properties:

• v [Optional] The cell value. The data type should match the column data type. If the cell is null, the v property should be null, though it can still have f and p properties.
• f [Optional] A string version of the v value, formatted for display. Typically the values will match, though they do not need to, so if you specify Date(2008, 0, 1) for v, you should specify "January 1, 2008" or some such string for this property. This value is not checked against the v value. The visualization will not use this value for calculation, only as a label for display. If omitted, a string version of v will be automatically generated using the default formatter. The f values can be modified using your own formatter, or set with setFormattedValue() or setCell(), or retrieved with getFormattedValue().
• p [Optional] An object that is a map of custom values applied to the cell. These values can be of any JavaScript type. If your visualization supports any cell-level properties, it will describe them. These properties can be retrieved by the getProperty() and getProperties() methods. Example: p:{style: 'border: 1px solid green;'}.

Cells in the row array should be in the same order as their column descriptions in cols. To indicate a null cell, you can specify null, leave a blank for a cell in an array, or omit trailing array members. So, to indicate a row with null for the first two cells, you could specify [ , , {cell_val}] or [null, null, {cell_val}].

Here is a sample table object with three columns, filled with three rows of data:

{
  cols: [{id: 'A', label: 'NEW A', type: 'string'},
         {id: 'B', label: 'B-label', type: 'number'},
         {id: 'C', label: 'C-label', type: 'date'}
  ],
  rows: [{c:[{v: 'a'},
             {v: 1.0, f: 'One'},
             {v: new Date(2008, 1, 28, 0, 31, 26), f: '2/28/08 12:31 AM'}
        ]},
         {c:[{v: 'b'},
             {v: 2.0, f: 'Two'},
             {v: new Date(2008, 2, 30, 0, 31, 26), f: '3/30/08 12:31 AM'}
        ]},
         {c:[{v: 'c'},
             {v: 3.0, f: 'Three'},
             {v: new Date(2008, 3, 30, 0, 31, 26), f: '4/30/08 12:31 AM'}
        ]}
  ]
}

p Property

The table-level p property is a map of custom values applied to the whole DataTable. These values can be of any JavaScript type. If your visualization supports any datatable-level properties, it will describe them; otherwise, this property will be available for application use. Example: p:{className: 'myDataTable'}.

DataView Class

A read-only view of an underlying DataTable. A DataView allows selection of only a subset of the columns and/or rows. It also allows reordering columns/rows, and duplicating columns/rows.

A view is a live window on the underlying DataTable, not a static snapshot of data. However, you still must be careful when changing the structure of the table itself, as described here:

• Adding or removing columns from the underlying table will not be reflected by the view, and might cause unexpected behavior in the view; you will have to create a new DataView from the DataTable to pick up these changes.
• Adding or removing rows from the underlying table is safe and changes will be propagated to the view immediately (but you must call draw() on any visualizations after this change to have the new row set rendered). Note that if your view has filtered out rows by calling one of the setRows() or hideRows() methods, and you add or remove rows from the underlying table, the behavior is unexpected; you must create a new DataView to reflect the new table.
• Changing cell values in existing cells is safe, and changes are immediately propagated to the DataView (but you must call draw() on any visualizations after this change to have the new cell values rendered).

It is also possible to create a DataView from another DataView. Note that whenever an underlying table or view is mentioned, it refers to the level immediately below this level. In other words, it refers to the data object used to construct this DataView.

DataView also supports calculated columns; these are columns whose value is calculated on the fly using a function that you supply. So, for example, you can include a column that is a sum of two preceding columns, or a column that calculates and shows the calendar quarter of a date from another column. See setColumns() for more details.

When you modify a DataView by hiding or showing rows or columns, the visualization will not be affected until you call draw() on the visualization again.

You can combine DataView.getFilteredRows() with DataView.setRows() to create a DataView with an interesting subset of data, as shown here:

var data = new google.visualization.DataTable();
data.addColumn('string', 'Employee Name');
data.addColumn('date', 'Start Date');
data.addRows(6);
data.setCell(0, 0, 'Mike');
data.setCell(0, 1, new Date(2008, 1, 28));
data.setCell(1, 0, 'Bob');
data.setCell(1, 1, new Date(2007, 5, 1));
data.setCell(2, 0, 'Alice');
data.setCell(2, 1, new Date(2006, 7, 16));
data.setCell(3, 0, 'Frank');
data.setCell(3, 1, new Date(2007, 11, 28));
data.setCell(4, 0, 'Floyd');
data.setCell(4, 1, new Date(2005, 3, 13));
data.setCell(5, 0, 'Fritz');
data.setCell(5, 1, new Date(2007, 9, 2));

// Create a view that shows everyone hired since 2007.
var view = new google.visualization.DataView(data);
view.setRows(view.getFilteredRows([{column: 1, minValue: new Date(2007, 0, 1)}]));
var table = new google.visualization.Table(document.getElementById('test_dataview'));
table.draw(view, {sortColumn: 1});

Constructors

There are two ways to create a new DataView instance:

Constructor 1

var myView = new google.visualization.DataView(data)

data

A DataTable or DataView used to initialize the view. By default, the view contains all the columns and rows in the underlying data table or view, in the original order. To hide or show rows or columns in this view, call the appropriate set...() or hide...() methods.

See also:

setColumns(), hideColumns(), setRows(), hideRows().

Constructor 2

This constructor creates a new DataView by assigning a serialized DataView to a DataTable. It helps you recreate the DataView that you serialized using DataView.toJSON().

var myView = google.visualization.DataView.fromJSON(data, viewAsJson)

data

The DataTable object that you used to create the DataView, on which you called DataView.toJSON(). If this table is any different from the original table, you will get unpredictable results.

viewAsJson

The JSON string returned by DataView.toJSON(). This is a description of which rows to show or hide from the data DataTable.

Methods

// Show some columns directly from the underlying data.
// Shows column 3 twice.
view.setColumns([3, 4, 3, 2]);

// Underlying table has a column specifying a value in centimeters.
// The view imports this directly, and creates a calculated column
// that converts the value into inches.
view.setColumns([1,{calc:cmToInches, type:'number', label:'Height in Inches'}]);
function cmToInches(dataTable, rowNum){
  return Math.floor(dataTable.getValue(rowNum, 1) / 2.54);
}

ChartWrapper Class

A ChartWrapper class is used to wrap your chart and handle all loading, drawing, and Datasource querying for your chart. The class exposes convenience methods for setting values on the chart and drawing it. This class simplifies reading from a data source, because you do not have to create a query callback handler. You can also use it to save a chart easily for reuse.

Another bonus of using ChartWrapper is that you can reduce the number of library loads by using dynamic loading. Additionally, you don't need to load the packages explicitly since ChartWrapper will handle looking up and loading the chart packages for you. See the examples below for details.

However, ChartWrapper currently only propagates a subset of events thrown by charts: select, ready, and error. Other events are not transmitted through the ChartWrapper instance; to get other events, you must call getChart() and subscribe to events directly on the chart handle, as shown here:

var wrapper;
function drawVisualization() {

  // Draw a column chart
  wrapper = new google.visualization.ChartWrapper({
    chartType: 'ColumnChart',
    dataTable: [['Germany', 'USA', 'Brazil', 'Canada', 'France', 'RU'],
                [700, 300, 400, 500, 600, 800]],
    options: {'title': 'Countries'},
    containerId: 'visualization'
  });

  // Never called.
  google.visualization.events.addListener(wrapper, 'onmouseover', uselessHandler);

  // Must wait for the ready event in order to
  // request the chart and subscribe to 'onmouseover'.
  google.visualization.events.addListener(wrapper, 'ready', onReady);

  wrapper.draw();

  // Never called
  function uselessHandler() {
    alert("I am never called!");
  }

  function onReady() {
    google.visualization.events.addListener(wrapper.getChart(), 'onmouseover', usefulHandler);
  }

  // Called
  function usefulHandler() {
    alert("Mouseover event!");
  }
}

Constructor

ChartWrapper(opt_spec)

opt_spec

[Optional] - Either a JSON object defining the chart, or a serialized string version of that object. The format of this object is shown in the drawChart() documentation. If not specified, you must set all the appropriate properties using the set... methods exposed by this object.

Methods

ChartWrapper exposes the following additional methods:

Events

The ChartWrapper object throws the following events. Note that you must call ChartWrapper.draw() before any events will be thrown.

Example

The following two snippets create an equivalent line chart. The first example uses JSON literal notation to define the chart; the second uses ChartWrapper methods to set these values.

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
<title>Google Visualization API Sample</title>
<!--
  One script tag loads all the required libraries!
-->
<script type="text/javascript"
      src='https://www.gstatic.com/charts/loader.js'></script>
<script>
  google.charts.load('current);
  google.charts.setOnLoadCallback(drawVisualization);

  function drawVisualization() {
    var wrap = new google.visualization.ChartWrapper({
       'chartType':'LineChart',
       'dataSourceUrl':'http://spreadsheets.google.com/tq?key=pCQbetd-CptGXxxQIG7VFIQ&pub=1',
       'containerId':'visualization',
       'query':'SELECT A,D WHERE D > 100 ORDER BY D',
       'options': {'title':'Population Density (people/km^2)', 'legend':'none'}
       });
     wrap.draw();
  }
</script>
</head>
<body>
  <div id="visualization" style="height: 400px; width: 400px;"></div>
</body>
</html>

Same chart, now using setter methods:

<!DOCTYPE html>
<html>
<head>
<meta http-equiv='content-type' content='text/html; charset=utf-8'/>
<title>Google Visualization API Sample</title>
<!-- One script tag loads all the required libraries!
-->
<script type="text/javascript"
    src='https://www.gstatic.com/charts/loader.js'></script>
<script type="text/javascript">
  google.charts.load('current');
  google.charts.setOnLoadCallback(drawVisualization);
  function drawVisualization() {
    // Define the chart using setters:
    var wrap = new google.visualization.ChartWrapper();
    wrap.setChartType('LineChart');
    wrap.setDataSourceUrl('http://spreadsheets.google.com/tq?key=pCQbetd-CptGXxxQIG7VFIQ&pub=1');
    wrap.setContainerId('visualization');
    wrap.setQuery('SELECT A,D WHERE D > 100 ORDER BY D');
    wrap.setOptions({'title':'Population Density (people/km^2)', 'legend':'none'});
    wrap.draw();
  }
</script>
</head>
<body>
  <div id='visualization' style='height: 400px; width: 400px;'></div>
</body>
</html>

ChartEditor Class

The ChartEditor class is used to open an in-page dialog box that enables a user to customize a visualization on the fly.

To use ChartEditor:

1. Load the charteditor package. In google.charts.load(), load the package 'charteditor'. You do not need to load the packages for the chart type that you render in the editor; the chart editor will load any package for you as needed.
2. Create a ChartWrapper object that defines the chart for the user to customize. This chart will be shown in the dialog, and the user uses the editor to redesign the chart, change chart types, or even change the source data.
3. Create a new ChartEditor instance, and register to listen for the "ok" event. This event is thrown when the user clicks the "OK" button on the dialog. When received, you should call ChartEditor.getChartWrapper() to retrieve the user-modified chart.
4. Call ChartEditor.openDialog(), passing in the ChartWrapper. This opens the dialog. The dialog buttons enable the user to close the editor. The ChartEditor instance is available as long as it is in scope; it is not automatically destroyed after the user closes the dialog.
5. To update the chart in code, call setChartWrapper().

Methods

Options

The chart editor supports the following options:

Events

The chart editor throws the following events:

Example

The following example code opens a chart editor dialog with a populated line chart. If the user clicks "OK", the edited chart will be saved to the specified <div> on the page.

<!DOCTYPE html>
<html>
<head>
  <meta http-equiv="content-type" content="text/html; charset=utf-8"/>
  <title>
    Google Visualization API Sample
  </title>
  <script type="text/javascript"
    src="https://www.gstatic.com/charts/loader.js"></script>
  <script type="text/javascript">
    google.charts.load('current', {packages: ['charteditor']});
  </script>
  <script type="text/javascript">
    google.charts.setOnLoadCallback(loadEditor);
    var chartEditor = null;

    function loadEditor() {
      // Create the chart to edit.
      var wrapper = new google.visualization.ChartWrapper({
         'chartType':'LineChart',
         'dataSourceUrl':'http://spreadsheets.google.com/tq?key=pCQbetd-CptGXxxQIG7VFIQ&pub=1',
         'query':'SELECT A,D WHERE D > 100 ORDER BY D',
         'options': {'title':'Population Density (people/km^2)', 'legend':'none'}
      });

      chartEditor = new google.visualization.ChartEditor();
      google.visualization.events.addListener(chartEditor, 'ok', redrawChart);
      chartEditor.openDialog(wrapper, {});
    }

    // On "OK" save the chart to a <div> on the page.
    function redrawChart(){
      chartEditor.getChartWrapper().draw(document.getElementById('vis_div'));
    }

  </script>
</head>
<body>
  <div id="vis_div" style="height: 400px; width: 600px;"></div>
</body>
</html>

Data Manipulation Methods

The google.visualization.data namespace holds static methods to perform SQL-like operations on DataTable objects, for example joining them or grouping by column value.

The google.visualization.data namespace exposes the following methods:

group()

Takes a populated DataTable object and performs a SQL-like GROUP BY operation, returning a table with rows grouped by the specified column values. Note that this does not modify the input DataTable.

The returned table includes one row for each combination of values in the specified key columns. Each row includes the key columns, plus one column with an aggregated column value over all rows that match the key combination (for example, a sum or count of all values in the specified column).

The google.visualization.data namespace includes several useful aggregation values (for example, sum and count), but you can define your own (for example, standardDeviation or secondHighest). Instructions on how to define your own aggregator are given after the method description.

Syntax

google.visualization.data.group(data_table, keys, columns)

data_table

The input DataTable. This will not be modified by calling group().

keys

An array of numbers and/or objects specifying which columns to group by. The result table includes every column in this array, as well as every column in columns. If a number, this is a column index of the input DataTable to group by. If an object, it will include a function that can modify the specified column (for example, add 1 to the value in that column). The object must have the following properties:

• column - A number that is a column index from dt to apply the transformation to.
• modifier - A function that accepts one value (the cell value in that column for each row), and returns the modified value. This function is used to modify the column value to assist in the grouping: for example, by calling a whichQuarter function that calculates a quarter from a date column, so the API can group rows by quarter. The calculated value is displayed in the key columns in the returned table. This function can be declared inline inside this object, or it can be a function that you define elsewhere in your code (it must be within the calling scope). The API provides one simple modifier function; here are instructions on how to create your own, more useful functions. You must know the data type that this function can accept, and call it only on columns of that type. You must also know the return type of this function, and declare it in the type property described next.
• type - The type returned by the function modifier. This should be a JavaScript string type name, for example: 'number' or 'boolean'.
• label - [Optional] A string label to assign this column in the returned DataTable.
• id - [Optional] A string ID to assign this column in the returned DataTable.

Examples: [0], [0,2], [0,{column:1, modifier:myPlusOneFunc, type:'number'},2]

columns

[Optional] Lets you specify which columns, in addition to key columns, to include in the output table. Because all rows in the row group are compressed into a single output row, you must determine what value to display for that row group. For example, you could choose to show the column value from the first row in the set, or an average of all rows in that group. columns is an array of objects, with the following properties:

• column - A number specifying the index of the column to show.
• aggregation - A function that accepts an array of all values of this column in this row group and returns a single value to display in the result row. The return value must be of the type specified by the object's type property. Details on creating your own aggregation function are given below. You must know what data types this method accepts and only call it on columns of the appropriate type. The API provides several useful aggregation functions. See Provided Aggregation Functions below for a list, or Creating an aggregation function to learn how to write your own aggregation function.
• type - The return type of the aggregation function. This should be a JavaScript string type name, for example: 'number' or 'boolean'.
• label - [Optional] A string label to apply to this column in the returned table.
• id - [Optional] A string ID to apply to this column in the returned table.

Return Value

A DataTable with one column for each column listed in keys and one column for each column listed in columns. The table is sorted by key rows, from left to right.

Example

// This call will group the table by column 0 values.
// It will also show column 3, which will be a sum of
// values in that column for that row group.
var result = google.visualization.data.group(
  dt,
  [0],
  [{'column': 3, 'aggregation': google.visualization.data.sum, 'type': 'number'}]
);

*Input table*
1  'john'  'doe'            10
1  'jane'  'doe'           100
3  'jill'  'jones'          50
3  'jack'  'jones'          75
5  'al'    'weisenheimer'  500

*Output table*
1  110
3  125
5  500

Provided Modifier Functions

The API provides the following modifier functions that you can pass into the keys. modifier parameter to customize grouping behavior.

Provided Aggregation Functions

The API provides the following aggregation functions that you can pass into the columns. aggregation parameter array.

Creating a modifier function

You can create a modifier function to perform a simple transformation onkey values before the group() function groups your rows. This function takes a single cell value, performs an action on it (for example, adds 1 to the value), and returns it. The input and return types need not be the same type, but the caller must know the input and output types. Here's an example of a function that accepts a date and returns the quarter:

// Input type: Date
// Return type: number (1-4)
function getQuarter(someDate) {
  return Math.floor(someDate.getMonth()/3) + 1;
}

Creating an aggregation function

You can create an aggregation function that accepts a set of column values in a row group and returns a single number: for example, returning a count or average of values. Here is an implementation of the provided count aggregation function, which returns a count of how many rows are in the row group:

// Input type: Array of any type
// Return type: number
function count(values) {
  return values.length;
}

join()

This method joins two data tables (DataTable or DataView objects) into a single results table, similar to a SQL JOIN statement. You specify one or more column pairs (key columns) between the two tables, and the output table includes the rows according to a join method that you specify: only rows where both keys match; all rows from one table; or all rows from both tables, whether or not the keys match. The results table includes only the key columns, plus any additional columns that you specify. Note that dt2 cannot have duplicate keys, but dt1 can. The term "key" means the combination of all key column values, not a specific key column value; so if a row has cell values A | B | C and columns 0 and 1 are key columns, then the key for that row is AB.

Syntax

google.visualization.data.join(dt1, dt2, joinMethod,
                                 keys, dt1Columns, dt2Columns);

dt1

A populated DataTable to join with dt2.

dt2

A populated DataTable to join with dt1. This table cannot have multiple identical keys (where a key is a combination of key column values).

joinMethod

A string specifying the join type. If dt1 has multiple rows that match a dt2 row, the output table will include all matching dt1 rows. Choose from the following values:

• 'full' - The output table includes all rows from both tables, regardless of whether keys match. Unmatched rows will have null cell entries; matched rows are joined.
• 'inner' - The full join filtered to include only rows where the keys match.
• 'left' - The output table includes all rows from dt1, whether or not there are any matching rows from dt2.
• 'right' - The output table includes all rows from dt2, whether or not there are any matching rows from dt1.

keys

An array of key columns to compare from both tables. Each pair is a two element array, the first is a key in dt1, the second is a key in dt2. This array can specify columns by their index, id, or label, see getColumnIndex.
Columns must be the same type in both tables. All specified keys must match according to the rule given by joinMethod in order to include a row from the table. Key columns are always included in the output table. Only dt1, the left-hand table, can include duplicate keys; keys in dt2 must be unique. The term "key" here means a unique set of key columns, not individual column values. For example, if your key columns were A and B, the following table would have only unique key values (and could thus be used as dt2):

A	B
Jen	Red
Jen	Blue
Fred	Red

Example: [[0,0], [2,1]] compares values from the first column in both tables as well as the third column from dt1 with the second column from dt2.

dt1Columns

An array of columns from dt1 to include in the output table, in addition to dt1's key columns. This array can specify columns by their index, id, or label, see getColumnIndex.

dt2Columns

An array of columns from dt2 to include in the output table, in addition to dt2's key columns. This array can specify columns by their index, id, or label, see getColumnIndex.

Return Value

A DataTable with the key columns, dt1Columns, and dt2Columns. This table is sorted by the key columns, from left to right. When joinMethod is 'inner', all key cells should be populated. For other join methods, if no matching key is found, the table will have a null for any unmatched key cells.

Examples

*Tables*
dt1                        dt2
bob  | 111 | red           bob   | 111 | point
bob  | 111 | green         ellyn | 222 | square
bob  | 333 | orange        jane  | 555 | circle
fred | 555 | blue          jane  | 777 | triangle
jane | 777 | yellow        fred  | 666 | dodecahedron
* Note that right table has duplicate Jane entries, but the key we will use is
* columns 0 and 1. The left table has duplicate key values, but that is
* allowed.

*Inner join* google.visualization.data.join(dt1, dt2, 'inner', [[0,0],[1,1]], [2], [2]);
bob  | 111 | red    | point
bob  | 111 | green  | point
jane | 777 | yellow | triangle
* Note that both rows from dt1 are included and matched to
* the equivalent dt2 row.


*Full join* google.visualization.data.join(dt1, dt2, 'full', [[0,0],[1,1]], [2], [2]);
bob   | 111 | red    | point
bob   | 111 | green  | point
bob   | 333 | orange | null
ellyn | 222 | null | square
fred  | 555 | blue   | null
fred  | 666 | null | dodecahedron
jane  | 555 | null | circle
jane  | 777 | yellow | triangle


*Left join*  google.visualization.data.join(dt1, dt2, 'left', [[0,0],[1,1]], [2], [2]);
bob  | 111 | red | point
bob  | 111 | green | point
bob  | 333 | orange | null
fred | 555 | blue | null
jane | 777 | yellow | triangle


*Right join*  google.visualization.data.join(dt1, dt2, 'right', [[0,0],[1,1]], [2], [2]);
bob   | 111 | red | point
bob   | 111 | green | point
ellyn | 222 | null | square
fred  | 666 | null | dodecahedron
jane  | 555 | null | circle
jane  | 777 | yellow | triangle

Formatters

The Google Visualization API provides formatters that can be used to reformat data in a visualization. These formatters change the formatted value of the specified column in all rows. Note that:

• Formatters modify only the formatted values, not the underlying values. For example, the displayed value would be "$1,000.00" but the underlying value would still be "1000".
• Formatters only affect one column at a time; to reformat multiple columns, apply a formatter to each column that you want to change.
• If you also use user-defined formatters, certain Google Visualization formatters will override all user-defined formatters.

The actual formatting applied to the data is derived from the locale the API has been loaded with. For more details, see loading charts with a specific locale .

Important: Formatters can only be used with a DataTable; they cannot be used with a DataView (DataView objects are read-only).

Here are the general steps for using a formatter:

1. Get your populated DataTable object.
2. For each column that you want to reformat:
   1. Create an object that specifies all the options for your formatter. This is a basic JavaScript object with a set of properties and values. Look at your formatter's documentation to see what properties are supported. (Optionally, you can pass in an object literal notation object specifying your options.)
   2. Create your formatter, passing in your options object.
   3. Call formatter.format(table, colIndex), passing in the DataTable and the (zero-based) column number of the data to reformat. Note that you can only apply a single formatter to each column; applying a second formatter will simply overwrite the effects of the first.
      Important: Many formatters require HTML tags to display special formatting; if your visualization supports an allowHtml option, you should set it to true.

Here is an example of changing the formatted date values of a date column to use a long date format ("January 1, 2009"):

var data = new google.visualization.DataTable();
data.addColumn('string', 'Employee Name');
data.addColumn('date', 'Start Date');
data.addRows(3);
data.setCell(0, 0, 'Mike');
data.setCell(0, 1, new Date(2008, 1, 28));
data.setCell(1, 0, 'Bob');
data.setCell(1, 1, new Date(2007, 5, 1));
data.setCell(2, 0, 'Alice');
data.setCell(2, 1, new Date(2006, 7, 16));

// Create a formatter.
// This example uses object literal notation to define the options.
var formatter = new google.visualization.DateFormat({formatType: 'long'});

// Reformat our data.
formatter.format(data, 1);

// Draw our data
var table = new google.visualization.Table(document.getElementById('dateformat_div'));
table.draw(data, {showRowNumber: true});

Most formatters expose the following two methods:

Method	Description
google.visualization.formatter_name(options)	Constructor, where formatter_name is a specfic formatterclass name. options - A generic JavaScript object that specifies the options for that formatter. This object is a generic object with property/value pairs with properties specific to that formatter. See the documentationfor your specific formatter to learn what options are supported. Here are two example ways to call the constructor for the DateFormat object, passing in two properties: // Object literal technique var formatter = new google.visualization.DateFormat({formatType: 'long', timeZone: -5}); // Equivalent property setting technique var options = new Object(); options['formatType'] = 'long'; options['timeZone'] = -5; var formatter = new google.visualization.DateFormat(options);
format(data, colIndex)	Reformats the data in the specified column. data - A DataTable containing the data to reformat. You cannot use a DataView here. colIndex - The zero-based index of the column to format. To format multiple columns, you must call this method multiple times, with different colIndex values.

 

The Google Visualization API provides the following formatters:

Formatter Name	Description
ArrowFormat	Adds an up or down arrow, indicating whether the cell value is above or below a specified value.
BarFormat	Adds a colored bar, the direction and color of which indicates whether the cell value is above or below a specified value.
ColorFormat	Colors a cell according to whether the values fall within a specified range.
DateFormat	Formats a Date or DateTime value in several different ways, including "January 1, 2009," "1/1/09" and "Jan 1, 2009."
NumberFormat	Formats various aspects of numeric values.
PatternFormat	Concatenates cell values on the same row into a specified cell, along with arbitrary text.

ArrowFormat

Adds an up or down arrow to a numeric cell, depending on whether the value is above or below a specified base value. If equal to the base value, no arrow is shown.

Options

ArrowFormat supports the following options, passed in to the constructor:

Option	Description
base	A number indicating the base value, used to compare against the cell value. If the cell value is higher, the cell will include a green up arrow; if the cell value is lower, it will include a red down arrow; if the same, no arrow.

Sample code

var data = new google.visualization.DataTable();
data.addColumn('string', 'Department');
data.addColumn('number', 'Revenues Change');
data.addRows([
  ['Shoes', {v:12, f:'12.0%'}],
  ['Sports', {v:-7.3, f:'-7.3%'}],
  ['Toys', {v:0, f:'0%'}],
  ['Electronics', {v:-2.1, f:'-2.1%'}],
  ['Food', {v:22, f:'22.0%'}]
]);

var table = new google.visualization.Table(document.getElementById('arrowformat_div'));

var formatter = new google.visualization.ArrowFormat();
formatter.format(data, 1); // Apply formatter to second column

table.draw(data, {allowHtml: true, showRowNumber: true});

BarFormat

Adds a colored bar to a numeric cell indicating whether the cell value is above or below a specified base value.

Options

BarFormat supports the following options, passed in to the constructor:

Option	Example Description
base	A number that is the base value to compare the cell value against. If the cell value is higher, it will be drawn to the right of the base; if lower, it will be drawn to the left. Default value is 0.
colorNegative	A string indicating the negative value section of bars. Possible values are 'red', 'green' and 'blue'; default value is 'red'.
colorPositive	A string indicating the color of the positive value section of bars. Possible values are 'red', 'green' and 'blue'. Default is 'blue'.
drawZeroLine	A boolean indicating if to draw a 1 pixel dark base line when negative values are present. The dark line is there to enhance visual scanning of the bars. Default value is 'false'.
max	The maximum number value for the bar range. Default value is the highest value in the table.
min	The minimum number value for the bar range. Default value is the lowest value in the table.
showValue	If true, shows values and bars; if false, shows only bars. Default value is true.
width	Thickness of each bar, in pixels. Default value is 100.

Sample code

var data = new google.visualization.DataTable();
data.addColumn('string', 'Department');
data.addColumn('number', 'Revenues');
data.addRows([
  ['Shoes', 10700],
  ['Sports', -15400],
  ['Toys', 12500],
  ['Electronics', -2100],
  ['Food', 22600],
  ['Art', 1100]
]);

var table = new google.visualization.Table(document.getElementById('barformat_div'));

var formatter = new google.visualization.BarFormat({width: 120});
formatter.format(data, 1); // Apply formatter to second column

table.draw(data, {allowHtml: true, showRowNumber: true, width: '100%', height: '100%'});

ColorFormat

Assigns colors to the foreground or background of a numeric cell, depending on the cell value. This formatter is an unusual, in that it doesn't take its options in the constructor. Instead, you should call addRange() or addGradientRange() as many times as you want, to add color ranges, before calling format(). Colors can be specified in any acceptable HTML format, for example "black", "#000000", or "#000".

Methods

ColorFormat supports the following methods:

Method	Description
google.visualization.ColorFormat()	Constructor. Takes no arguments.
addRange(from, to, color, bgcolor)	Specifies a foreground color and/or background color to a cell, depending on the cell value. Any cell with a value in the specified from—to range will be assigned color and bgcolor. It is important to realize that the range is non-inclusive, because creating a range from 1—1,000 and a second from 1,000— 2,000 will not cover the value 1,000! from - [String, Number, Date, DateTime, or TimeOfDay] The lower boundary (inclusive) of the range, or null. If null, it will match -∞. String boundaries are compared alphabetically against string values. to - [String, Number, Date, DateTime, or TimeOfDay] The high boundary (non-inclusive) of the range, or null. If null, it will match +∞. String boundaries are compared alphabetically against string values. color - The color to apply to text in matching cells. Values can be either '#RRGGBB' values or defined color constants, (example: '#FF0000' or 'red'). bgcolor - The color to apply to the background of matching cells. Values can be either '#RRGGBB' values or defined color constants, (example: '#FF0000' or 'red').
addGradientRange(from, to, color, fromBgColor, toBgColor)	Assigns a background color from a range, according to the cell value. The color is scaled to match the cell's value within a range from a lower boundary color to an upper boundary color. Note that this method cannot compare string values, as addRange() can. Tip: Color ranges are often hard for viewers to gauge accurately; the simplest and easiest to read range is from a fully saturated color to white (e.g., #FF0000—FFFFFF). from - [Number, Date, DateTime, or TimeOfDay] The lower boundary (inclusive) of the range, or null. If null, it will match -∞. to - [Number, Date, DateTime, or TimeOfDay] The higher boundary (non-inclusive) of the range, or null. If null, it will match +∞. color - The color to apply to text in matching cells. This color is the same for all cells, no matter what their value. fromBgColor - The background color for cells holding values at the low end of the gradient. Values can be either '#RRGGBB' values or defined color constants, (example: '#FF0000' or 'red'). toBgColor - The background color for cells holding values at the high end of the gradient. Values can be either '#RRGGBB' values or defined color constants, (example: '#FF0000' or 'red').
format(dataTable, columnIndex)	The standard format() method to apply formatting to the specified column.

Sample code

var data = new google.visualization.DataTable();
data.addColumn('string', 'Department');
data.addColumn('number', 'Revenues');
data.addRows([
  ['Shoes', 10700],
  ['Sports', -15400],
  ['Toys', 12500],
  ['Electronics', -2100],
  ['Food', 22600],
  ['Art', 1100]
]);

var table = new google.visualization.Table(document.getElementById('colorformat_div'));

var formatter = new google.visualization.ColorFormat();
formatter.addRange(-20000, 0, 'white', 'orange');
formatter.addRange(20000, null, 'red', '#33ff33');
formatter.format(data, 1); // Apply formatter to second column

table.draw(data, {allowHtml: true, showRowNumber: true, width: '100%', height: '100%'});

DateFormat

Formats a JavaScript Date value in a variety of ways, including "January 1, 2016," "1/1/16" and "Jan 1, 2016".

Options

DateFormat supports the following options, passed in to the constructor:

Option	Description
formatType	A quick formatting option for the date. The following string values are supported, reformatting the date February 28, 2016 as shown: 'short' - Short format: e.g., "2/28/16" 'medium' - Medium format: e.g., "Feb 28, 2016" 'long' - Long format: e.g., "February 28, 2016" You cannot specify both formatType and pattern.
pattern	A custom format pattern to apply to the value, similar to the ICU date and time format. For example: var formatter3 = new google.visualization.DateFormat({pattern: "EEE, MMM d, ''yy"}); You cannot specify both formatType and pattern. You can read more details about patterns in the next section.
timeZone	The time zone in which to display the date value. This is a numeric value, indicating GMT + this number of time zones (can be negative). Date object are created by default with the assumed time zone of the computer on which they are created; this option is used to display that value in a different time zone. For example, if you created a Date object of 5pm noon on a computer located in Greenwich, England, and specified timeZone to be -5 (options['timeZone'] = -5, or Eastern Pacific Time in the US), the value displayed would be 12 noon.

Methods

DateFormat supports the following methods:

Method	Description
google.visualization.DateFormat(options)	Constructor. See the options section above for more info.
format(dataTable, columnIndex)	The standard format() method to apply formatting to the specified column.
formatValue(value)	Returns the formatted value of a given value. This method does not require a DataTable.

Sample code

function drawDateFormatTable() {
  var data = new google.visualization.DataTable();
  data.addColumn('string', 'Employee Name');
  data.addColumn('date', 'Start Date (Long)');
  data.addColumn('date', 'Start Date (Medium)');
  data.addColumn('date', 'Start Date (Short)');
  data.addRows([
    ['Mike', new Date(2008, 1, 28, 0, 31, 26),
             new Date(2008, 1, 28, 0, 31, 26),
             new Date(2008, 1, 28, 0, 31, 26)],
    ['Bob', new Date(2007, 5, 1, 0),
            new Date(2007, 5, 1, 0),
            new Date(2007, 5, 1, 0)],
    ['Alice', new Date(2006, 7, 16),
              new Date(2006, 7, 16),
              new Date(2006, 7, 16)]
  ]);

  // Create three formatters in three styles.
  var formatter_long = new google.visualization.DateFormat({formatType: 'long'});
  var formatter_medium = new google.visualization.DateFormat({formatType: 'medium'});
  var formatter_short = new google.visualization.DateFormat({formatType: 'short'});

  // Reformat our data.
  formatter_long.format(data, 1);
  formatter_medium.format(data,2);
  formatter_short.format(data, 3);

  // Draw our data
  var table = new google.visualization.Table(document.getElementById('dateformat_div'));
  table.draw(data, {showRowNumber: true, width: '100%', height: '100%'});
}

More About Date Patterns

Here are some more details on what patterns are supported:

The patterns are similar to the ICU date and time format, but the following patterns are not yet supported: A e D F g Y u w W. To avoid collision with patterns, any literal text you want to appear in the output should be surrounded by single quotes, except for the single quote, which should be doubled: e.g., "K 'o''clock.'".

Pattern	Description	Example Output
GG	Era designator.	"AD"
yy or yyyy	year.	1996
M	Month in year. For January: M produces 1 MM produces 01 MMM produces Jan MMMM produces January	"July" "07"
d	Day in month. Extra 'd' values will add leading zeros.	10
h	Hour in 12 hour scale. Extra 'h' values will add leading zeros.	12
H	Hour in 24 hour scale. Extra Hk' values will add leading zeros.	0
m	Minute in hour. Extra 'M' values will add leading zeros.	30
s	Second in minute. Extra 's' values will add leading zeros.	55
S	Fractional second. Extra 'S' values will be padded on the right with zeros.	978
E	Day of week. Following outputs for "Tuesday": E produces T EE or EEE Produce Tu or Tues EEEE Produces Tuesday	"Tues" "Tuesday"
aa	AM/PM	"PM"
k	Hour in day (1~24). Extra 'k' values will add leading zeros.	24
K	Hour in AM/PM (0~11). Extra 'k' values will add leading zeros.	0
z	Time zone. For time zone 5, produces "UTC+5"	"UTC+5"
Z	Time zone in RFC 822 format. For time zone -5: Z, ZZ, ZZZ produce -0500 ZZZZ and more produce "GMT -05:00"	"-0800" "GMT -05:00"
v	Time zone (generic).	"Etc/GMT-5"
'	escape for text	'Date='
''	single quote	''yy

NumberFormat

Describes how numeric columns should be formatted. Formatting options include specifying a prefix symbol (such as a dollar sign) or the punctuation to use as a thousands marker.

Options

NumberFormat supports the following options, passed in to the constructor:

Option	Description
decimalSymbol	A character to use as the decimal marker. The default is a dot (.).
fractionDigits	A number specifying how many digits to display after the decimal. The default is 2. If you specify more digits than the number contains, it will display zeros for the smaller values. Truncated values will be rounded (5 rounded up).
groupingSymbol	A character to be used to group digits to the left of the decimal into sets of three. Default is a comma (,).
negativeColor	The text color for negative values. No default value. Values can be any acceptable HTML color value, such as "red" or "#FF0000".
negativeParens	A boolean, where true indicates that negative values should be surrounded by parentheses. Default is true.
pattern	A format string. When provided, all other options are ignored, except negativeColor. The format string is a subset of the ICU pattern set . For instance, {pattern:'#,###%'} will result in output values "1,000%", "750%", and "50%" for values 10, 7.5, and 0.5.
prefix	A string prefix for the value, for example "$".
suffix	A string suffix for the value, for example "%".

Methods

NumberFormat supports the following methods:

Method	Description
google.visualization.NumberFormat(options)	Constructor. See the options section above for more info.
format(dataTable, columnIndex)	The standard format() method to apply formatting to the specified column.
formatValue(value)	Returns the formatted value of a given value. This method does not require a DataTable.

Sample code

var data = new google.visualization.DataTable();
data.addColumn('string', 'Department');
data.addColumn('number', 'Revenues');
data.addRows([
  ['Shoes', 10700],
  ['Sports', -15400],
  ['Toys', 12500],
  ['Electronics', -2100],
  ['Food', 22600],
  ['Art', 1100]
]);

var table = new google.visualization.Table(document.getElementById('numberformat_div'));

var formatter = new google.visualization.NumberFormat(
    {prefix: '$', negativeColor: 'red', negativeParens: true});
formatter.format(data, 1); // Apply formatter to second column

table.draw(data, {allowHtml: true, showRowNumber: true, width: '100%', height: '100%'});

PatternFormat

Enables you to merge the values of designated columns into a single column, along with arbitrary text. So, for example, if you had a column for first name and a column for last name, you could populate a third column with {last name}, {first name}. This formatter does not follow the conventions for the constructor and the format() method. See the Methods section below for instructions.

Methods

PatternFormat supports the following methods:

Method	Description
google.visualization.PatternFormat(pattern)	Constructor. Does not take an options object. Instead, it takes a string pattern parameter. This is a string that describes which column values to put into the destination column, along with any arbitrary text. Embed placeholders in your string to indicate a value from another column to embed. The placeholders are {#}, where # is a the index of a source column to use. The index is an index in the srcColumnIndices array from the format() method below. To include a literal { or } character, escape it like this: \{ or \}. To include a literal \ mark, escape it as \\. Sample code The following example demonstrates a constructor for a pattern that creates an anchor element, with the first and second elements taken from the format() method: var formatter = new google.visualization.PatternFormat( '<a href="mailto:{1}">{0}</a>');
format(dataTable, srcColumnIndices, opt_dstColumnIndex)	The standard formatting call, with a few additional parameters: dataTable - The DataTable on which to operate. srcColumnIndices - An array of one or more (zero-based) column indices to pull as the sources from the underlying DataTable. This will be used as a data source for the pattern parameter in the constructor. The column numbers do not have to be in sorted order. opt_dstColumnIndex - [optional] The destination column to place the output of the pattern manipulation. If not specified, the first element in srcColumIndices will be used as the destination. See the formatting examples after the table.

Here are a few example inputs and outputs for a four-column table.

Row before formatting (4 columns, last is blank):
John  |  Paul  |  Jones  |  [empty]

var formatter = new google.visualization.PatternFormat("{0} {1} {2}");
formatter.format(data, [0,1,2], 3);
Output:
  John  |  Paul  |  Jones  |  John Paul Jones

var formatter = new google.visualization.PatternFormat("{1}, {0}");
formatter.format(data, [0,2], 3);
Output:
  John  |  Paul  |  Jones  |  Jones, John

Sample code

The following example demonstrates how to combine data from two columns to create an email address. It uses a DataView object to hide the original source columns:

var data = new google.visualization.DataTable();
data.addColumn('string', 'Name');
data.addColumn('string', 'Email');
data.addRows([
  ['John Lennon', 'john@beatles.co.uk'],
  ['Paul McCartney', 'paul@beatles.co.uk'],
  ['George Harrison', 'george@beatles.co.uk'],
  ['Ringo Starr', 'ringo@beatles.co.uk']
]);

var table = new google.visualization.Table(document.getElementById('patternformat_div'));

var formatter = new google.visualization.PatternFormat(
    '<a href="mailto:{1}">{0}</a>');
// Apply formatter and set the formatted value of the first column.
formatter.format(data, [0, 1]);

var view = new google.visualization.DataView(data);
view.setColumns([0]); // Create a view with the first column only.

table.draw(view, {allowHtml: true, showRowNumber: true, width: '100%', height: '100%'});

GadgetHelper

A helper class to simplify writing Gadgets that use the Google Visualization API.

Constructor

google.visualization.GadgetHelper()

Methods

Method	Return Value	Description
createQueryFromPrefs(prefs)	google.visualization.Query	Static. Create a new instance of google.visualization.Query and set its properties according to values from the gadget preferences. The type of parameter prefs is _IG_Prefs Preference _table_query_url is used to set the Query data source URL. Preference _table_query_refresh_interval is used to set the Query refresh interval (in seconds).
validateResponse(response)	Boolean	Static. Parameter response is of type google.visualization.QueryResponse. Returns true if the response contains data. Returns false if the query execution failed and the response does not contain data. If an error occurred, this method displays an error message.

Query Classes

The following objects are available to send queries for data to an external data source, such as Google Spreadsheets.

• Query - Wraps the outgoing data request.
• QueryResponse - Handles the response from the data source.

Query

Represents a query that is sent to a data source.

Constructor

google.visualization.Query(dataSourceUrl, opt_options)

Parameters

dataSourceUrl

[Required, String] URL to send the query to. See the Charts and Spreadsheets documentation for Google Spreadsheets.

opt_options

[Optional, Object] A map of options for the request. Note: If you are accessing a restricted data source , you should not use this parameter. Here are the supported properties:

• sendMethod - [Optional, String] Specifies the method to use to send the query. Choose one of the following string values:
  • 'xhr' - Send the query using XmlHttpRequest.
  • 'scriptInjection' - Send the query using script injection.
  • 'makeRequest' - [Available only for gadgets, which are deprecated] Send the query using the Gadget API   makeRequest() method. If specified, you should also specify makeRequestParams.
  • 'auto' - Use the method specified by the tqrt URL parameter from the data source URL. tqrt can have the following values: 'xhr', 'scriptInjection', or 'makeRequest'. If tqrt is missing or has an invalid value, the default is 'xhr' for same-domain requests and 'scriptInjection' for cross-domain requests.
• makeRequestParams - [Object] A map of parameters for a makeRequest() query. Used and required only if sendMethod is 'makeRequest'.

Methods

Method	Return Value	Description
abort()	None	Stops the automated query sending that was started with setRefreshInterval().
setRefreshInterval(seconds)	None	Sets the query to automatically call the send method every specified duration (number of seconds), starting from the first explicit call to send. seconds is a number greater than or equal to zero. If you use this method, you should call it before calling the send method. Cancel this method either by calling it again with zero (the default), or by calling abort().
setTimeout(seconds)	None	Sets the number of seconds to wait for the data source to respond before raising a timeout error. seconds is a number greater than zero. The default timeout is 30 seconds. This method, if used, should be called before calling the send method.
setQuery(string)	None	Sets the query string. The value of the string parameter should be a valid query. This method, if used, should be called before calling the send method. Learn more about the Query language.
send(callback)	None	Sends the query to the data source. callback should be a function that will be called when the data source responds. The callback function will receive a single parameter of type google.visualization.QueryResponse.

QueryResponse

Represents a response of a query execution as received from the data source. An instance of this class is passed as an argument to the callback function that was set when Query.send was called.

Methods

Method	Return Value	Description
getDataTable()	DataTable	Returns the data table as returned by the data source. Returns null if the query execution failed and no data was returned.
getDetailedMessage()	String	Returns a detailed error message for queries that failed. If the query execution was successful, this method returns an empty string. The message returned is a message that is intended for developers, and may contain technical information, for example 'Column {salary} does not exist'.
getMessage()	String	Returns a short error message for queries that failed. If the query execution was successful, this method returns an empty string. The message returned is a short message that is intended for end users, for example 'Invalid Query' or 'Access Denied'.
getReasons()	Array of strings	Returns an array of zero of more entries. Each entry is a short string with an error or warning code that was raised while executing the query. Possible codes: access_denied The user does not have permissions to access the data source. invalid_query The specified query has a syntax error. data_truncated One or more data rows that match the query selection were not returned due to output size limits. (warning). timeout The query did not respond within the expected time.
hasWarning()	Boolean	Returns true if the query execution has any warning messages.
isError()	Boolean	Returns true if the query execution failed, and the response does not contain any data table. Returns <false> if the query execution was successful and the response contains a data table.

Error Display

The API provides several functions to help you display custom error messages to your users. To use these functions, provide a container element on the page (typically a <div>), into which the API will draw a formatted error message. This container can be either the visualization container element, or a container just for errors. If you specify the visualization containe element, the error message will be displayed above the visualization. Then call the appropriate function below to show, or remove, the error message.

All functions are static functions in the namespace google.visualization.errors.

Many visualizations can throw an error event; see error event below to learn more about that.

You can see an example custom error in the Query Wrapper Example.

Function	Return Value	Description
addError(container, message, opt_detailedMessage, opt_options)	String ID value that identifies the error object created. This is a unique value on the page, and can be used to remove the error or find its containing element.	Adds an error display block to the specified page element, with specified text and formatting. container - The DOM element into which to insert the error message. If the container cannot be found, the function will throw a JavaScript error. message - A string message to display. opt_detailedMessage - An optional detailed message string. By default, this is mouseover text, but that can be changed in the opt_options.showInToolTip property described below. opt_options - An optional object with properties that set various display options for the message. The following options are supported: showInTooltip - A boolean value where true shows the detailed message only as tooltip text, and false shows the detailed message in the container body after the short message. Default value is true. type - A string describing the error type, which determines which css styles should be applied to this message. The supported values are 'error' and 'warning'. Default value is 'error'. style - A style string for the error message. This style will override any styles applied to the warning type (opt_options.type). Example: 'background-color: #33ff99; padding: 2px;' Default value is an empty string. removable - A boolean value, where true means that the message can be closed by a mouse click from the user. Default value is false.
addErrorFromQueryResponse(container, response)	String ID value that identifies the error object created, or null if the response didn't indicate an error. This is a unique value on the page, and can be used to remove the error or find its containing element.	Pass a query response and error message container to this method: if the query response indicates a query error, displays an error message in the specified page element. If the query response is null, the method will throw a JavaScript error. Pass your QueryResponse received in your query handler to this message to display an error. It will also set the style of the display appropriate to the type (error or warning, similar to addError(opt_options.type)) container - The DOM element into which to insert the error message. If the container cannot be found, the function will throw a JavaScript error. response - A QueryResponse object received by your query handler in response to a query. If this is null, the method will throw a JavaScript error.
removeError(id)	Boolean: true if the error was removed; false otherwise.	Removes the error specified by ID from the page. id - The string ID of an error created using addError() or addErrorFromQueryResponse().
removeAll(container)	None	Removes all error blocks from a specified container. If the specified container does not exist, this will throw an error. container - The DOM element holding the error strings to remove. If the container cannot be found, the function will throw a JavaScript error.
getContainer(errorId)	Handle to a DOM element holding the error specified, or null if it could not be found.	Retrieves a handle to the container element holding the error specified by errorID. errorId - String ID of an error created using addError() or addErrorFromQueryResponse().

Events

Most visualizations fire events to indicate something has occurred. As a user of the chart, you would often want to listen to these events. If you code your own visualization, you might also want to trigger such events on your own.

The following methods enable developers to listen to events, remove existing event handlers or trigger events from inside a visualization.

• google.visualization.events.addListener() and google.visualization.events.addOneTimeListener() listen for events.
• google.visualization.events.removeListener() removes an existing listener
• google.visualization.events.removeAllListeners() removes all listeners of a specific chart
• google.visualization.events.trigger() fires an event.

addListener()

Call this method to register to receive events fired by a visualization hosted on your page. You should document what event arguments, if any, will be passed to the handling function.

google.visualization.events.addListener(source_visualization,
  event_name, handling_function)

source_visualization

A handle to the source visualization instance.

event_name

The string name of the event to listen for. A visualization should document which events it throws.

handling_function

The name of the local JavaScript function to call when source_visualization fires the event_name event. The handling function will be passed any event arguments as parameters.

Returns

A listener handler for the new listener. The handler can be used to later remove this listener if needed by calling google.visualization.events.removeListener().

Example

Here is an example of registering to receive the selection event

var table = new google.visualization.Table(document.getElementById('table_div'));
table.draw(data, options);

google.visualization.events.addListener(table, 'select', selectHandler);

function selectHandler() {
  alert('A table row was selected');
}

addOneTimeListener()

This is identical to addListener(), but is intended for events that should only be listened to once. Subsequent throws of the event will not invoke the handling function.

An example of when this is useful: every draw causes a ready event to be thrown. If you want only the first ready to execute your code, you'll want addOneTimeListener rather than addListener.

removeListener()

Call this method to unregister an existing event listener.

google.visualization.events.removeListener(listener_handler)

listener_handler

The listener handler to remove, as returned by google.visualization.events.addListener().

removeAllListeners()

Call this method to unregister all event listeners of a specific visualization instance.

google.visualization.events.removeAllListeners(source_visualization)

source_visualization

A handle to the source visualization instance from which all event listeners should be removed.

trigger()

Called by visualization implementers. Call this method from your visualization to fire an event with an arbitrary name and set of values.

google.visualization.events.trigger(source_visualization, event_name,
  event_args)

source_visualization

A handle to the source visualization instance. If you are calling this function from within a method defined by the sending visualization, you can simply pass in the this keyword.

event_name

A string name to call the event. You can choose any string value that you want.

event_args

[optional] A map of name/value pairs to pass to the receiving method. For example: {message: "Hello there!", score: 10, name: "Fred"}. You can pass null if no events are needed; the receiver should be prepared to accept null for this parameter.

Example

Here is an example of a visualization that throws a method named "select" when its onclick method is called. It does not pass back any values.

MyVisualization.prototype.onclick = function(rowIndex) {
  this.highlightRow(this.selectedRow, false); // Clear previous selection
  this.highlightRow(rowIndex, true); // Highlight new selection

  // Save the selected row index in case getSelection is called.
  this.selectedRow = rowIndex;

  // Trigger a select event.
  google.visualization.events.trigger(this, 'select', null);
}

Standard Visualization Methods and Properties

Every visualization should expose the following set of required and optional methods and properties. However, note that there is no type checking to enforce these standards, so you should read the documentation for each visualization.

• Constructor
• draw()
• getAction() [optional]
• getSelection() [optional]
• removeAction() [optional]
• setAction() [optional]
• setSelection() [optional]

Note: These methods are in the namespace of the visualization, not the google.visualization namespace.

Constructor

The constructor should have the name of your visualization class, and return an instance of that class.

visualization_class_name(dom_element)

dom_element

A pointer to a DOM element where the visualization should be embedded.

Example

var org = new google.visualization.OrgChart(document.getElementById('org_div')); 

draw()

Draws the visualization on the page. Behind the scenes this can be fetching a graphic from a server or creating the graphic on the page using the linked visualization code. You should call this method every time the data or options change. The object should be drawn inside the DOM element passed into the constructor.

draw(data[, options])

data

A DataTable or DataView holding the data to use to draw the chart. There is no standard method for extracting a DataTable from a chart.

options

[Optional] A map of name/value pairs of custom options. Examples include height and width, background colors, and captions. The visualization documentation should list which options are available, and should support default options if you do not specify this parameter. You can use the JavaScript object literal syntax to pass in an options map: e.g., {x:100, y:200, title:'An Example'}

Example

chart.draw(myData, {width: 400, height: 240, is3D: true, title: 'My Daily Activities'});

getAction()

This is optionally exposed by visualizations that have tooltips and allow tooltip actions.

Returns the tooltip action object with the requested actionID.

Example:

// Returns the action object with the ID 'alertAction'.
chart.getAction('alertAction');

getSelection()

This is optionally exposed by visualizations that want to let you access the currently selected data in the graphic.

selection_array getSelection()

Returns

selection_array   An array of selected objects, each one describing a data element in the underlying table used to create the visualization (a DataView or a DataTable). Each object has properties row and/or column, with the index of the row and/or column of the selected item in the underlying DataTable. If the row property is null, then the selection is a column; if the column property is null, then the selection is a row; if both are non-null, then it is a specific data item. You can call the DataTable.getValue() method to get the value of the selected item. The retrieved array can be passed into setSelection().

Example

function myClickHandler(){
  var selection = myVis.getSelection();
  var message = '';

  for (var i = 0; i < selection.length; i++) {
    var item = selection[i];
    if (item.row != null && item.column != null) {
      message += '{row:' + item.row + ',column:' + item.column + '}';
    } else if (item.row != null) {
      message += '{row:' + item.row + '}';
    } else if (item.column != null) {
      message += '{column:' + item.column + '}';
    }
  }
  if (message == '') {
    message = 'nothing';
  }
  alert('You selected ' + message);
}

removeAction()

This is optionally exposed by visualizations that have tooltips and allow tooltip actions.

Removes the tooltip action object with the requested actionID from your chart.

Example:

// Removes an action from chart with the ID of 'alertAction'.
chart.removeAction('alertAction');

setAction()

This is optionally exposed by visualizations that have tooltips and allow tooltip actions. It works only for core charts (bar, column, line, area, scatter, combo, bubble, pie, donut, candlestick, histogram, stepped area).

Sets a tooltip action to be executed when the user clicks on the action text.

setAction(action object)

The setAction method takes an object as its action parameter. This object should specify 3 properties: id— the ID of the action being set, text —the text that should appear in the tooltip for the action, and action — the function that should be run when a user clicks on the action text.

Any and all tooltip actions should be set prior to calling the chart's draw() method.

Example:

// Sets a tooltip action which will pop an alert box on the screen when triggered.
chart.setAction({
  id: 'alertAction',
  text: 'Trigger Alert',
  action: function() {
    alert('You have triggered an alert');
  }
});

The setAction method can also define two additional properties: visible and enabled. These properties should be functions that return boolean values indicating if the tooltip action will be visible and/or enabled.

Example:

// The visible/enabled functions can contain any logic to determine their state
// as long as they return boolean values.
chart.setAction({
  id: 'alertAction',
  text: 'Trigger Alert',
  action: function() {
    alert('You have triggered an alert');
  },
  visible: function() {
    return true;
  },
  enabled: function() {
    return true;
  }
});

setSelection()

Optionally selects a data entry in the visualization—for example, a point in an area chart, or a bar in a bar chart. When this method is called, the visualization should visually indicate what the new selection is. The implementation of setSelection() should not fire a "select" event. Visualizations may ignore part of the selection. For example, a table that can show only selected rows may ignore cell or column elements in its setSelection() implementation, or it can select the entire row.

Every time this method is called, all selected items are deselected, and the new selection list passed in should be applied. There is no explicit way to deselect individual items; to deselect individual items, call setSelection() with the items to remain selected; to deselect all elements, call setSelection(), setSelection(null), or setSelection([]).

setSelection(selection_array)

selection_array

An array of objects, each with a numeric row and/or column property. row and column are the zero-based row or column number of an item in the data table to select. To select a whole column, set row to null; to select a whole row, set column to null. Example: setSelection([{row:0,column:1},{row:1, column:null}]) selects the cell at (0,1) and the entire row 1.

Assorted Static Methods

This section contains various useful methods exposed in the google.visualization namespace.

arrayToDataTable()

This method takes in a two-dimensional array and converts it to a DataTable.

The column data types are determined automatically by the data provided. Column data types can also be specified using the object literal notation in the first row (the column header row) of the array (i.e. {label: 'Start Date', type: 'date'}). Optional data roles may be used as well, but they must be defined explicitly using object literal notation. Object literal notation may also be used for any cell, allowing you to define Cell Objects).

Syntax

google.visualization.arrayToDataTable(twoDArray, opt_firstRowIsData)

twoDArray

A two-dimensional array, where each row represents a row in the data table. If opt_firstRowIsData is false (the default), the first row will be interpreted as header labels. The data types of each column are interpreted automatically from the data given. If a cell has no value, specify a null or empty value as appropriate.

opt_firstRowIsData

Whether the first row defines a header row or not. If true, all rows are assumed to be data. If false, the first row is assumed to be a header row, and the values are assigned as column labels. Default is false.

Returns

A new DataTable.

Examples

The following code demonstrates three ways to create the same DataTable object:

// Version 1: arrayToDataTable method
var data2 = google.visualization.arrayToDataTable([
  [{label: 'Country', type: 'string'},
   {label: 'Population', type: 'number'},
   {label: 'Area', type: 'number'},
   {type: 'string', role: 'annotation'}],
  ['CN', 1324, 9640821, 'Annotated'],
  ['IN', 1133, 3287263, 'Annotated'],
  ['US', 304, 9629091, 'Annotated'],
  ['ID', 232, 1904569, 'Annotated'],
  ['BR', 187, 8514877, 'Annotated']
]);

// Version 2: DataTable.addRows
var data3 = new google.visualization.DataTable();
data3.addColumn('string','Country');
data3.addColumn('number','Population');
data3.addColumn('number','Area');
data3.addRows([
  ['CN', 1324, 9640821],
  ['IN', 1133, 3287263],
  ['US', 304, 9629091],
  ['ID', 232, 1904569],
  ['BR', 187, 8514877]
]);

// Version 3: DataTable.setValue
var data = new google.visualization.DataTable();
data.addColumn('string','Country');
data.addColumn('number', 'Population');
data.addColumn('number', 'Area');
data.addRows(5);
data.setValue(0, 0, 'CN');
data.setValue(0, 1, 1324);
data.setValue(0, 2, 9640821);
data.setValue(1, 0, 'IN');
data.setValue(1, 1, 1133);
data.setValue(1, 2, 3287263);
data.setValue(2, 0, 'US');
data.setValue(2, 1, 304);
data.setValue(2, 2, 9629091);
data.setValue(3, 0, 'ID');
data.setValue(3, 1, 232);
data.setValue(3, 2, 1904569);
data.setValue(4, 0, 'BR');
data.setValue(4, 1, 187);
data.setValue(4, 2, 8514877);

drawChart()

This method creates a chart in a single call. The advantage of using this method is that it requires slightly less code, and you can serialize and save visualizations as text strings for reuse. This method does not return a handle to the created chart, so you cannot assign method listeners to catch chart events.

Syntax

google.visualization.drawChart(chart_JSON_or_object)

chart_JSON_or_object

Either a JSON literal string or a JavaScript object, with the following properties (case-sensitive):

Property	Type	Required	Default	Description
chartType	String	Required	none	The class name of the visualization. The google.visualization package name can be omitted for Google charts. If the appropriate visualization library has not already been loaded, this method will load the library for you if this is a Google visualization; you must load third party visualizations explicitly. Examples: Table, PieChart, example.com.CrazyChart.
containerId	String	Required	none	The ID of the DOM element on your page that will host the visualization.
options	Object	Optional	none	An object describing the options for the visualization. You can use either JavaScript literal notation, or provide a handle to the object. Example: "options": {"width": 400, "height": 240, "is3D": true, "title": "Company Performance"}
dataTable	Object	Optional	None	A DataTable used to populate the visualization. This can be a literal JSON string representation of a DataTable, as described above, or a handle to a populated google.visualization.DataTable object, or a 2-dimensional array like that accepted by arrayToDataTable(opt_firstRowIsData=false) . You must specify either this property or the dataSourceUrl property.
dataSourceUrl	String	Optional	None	A data source query to populate the chart data (for example, a Google Spreadsheet). You must specify either this property or the dataTable property.
query	String	Optional	None	If specifying dataSourceUrl, you can optionally specify a SQL-like query string using the Visualization query language to filter or manipulate the data.
refreshInterval	Number	Optional	None	How often, in seconds, the visualization should refresh its query source. Use this only when specifying dataSourceUrl.
view	Object OR Array	Optional	None	Sets a DataView initializer object, which acts as a filter over the underlying data, as defined by either the dataTable or dataSourceUrl parameter. You can pass in either a string or DataView initializer object, like that returned by dataview.toJSON(). Example: "view": {"columns": [1, 2]} You can also pass in an array of DataView initializer objects, in which case the first DataView in the array is applied to the underlying data to create a new data table, and the second DataView is applied to the data table resulting from application of the first DataView, and so on.

Examples

Creates a table chart based on a spreadsheet data source, and includes the query SELECT A,D WHERE D > 100 ORDER BY D

<script type="text/javascript">
  google.charts.load('current');  // Note: No need to specify chart packages.
  function drawVisualization() {
    google.visualization.drawChart({
      "containerId": "visualization_div",
      "dataSourceUrl": "https://spreadsheets.google.com/a/google.com/tq?key=pCQbetd-CptGXxxQIG7VFIQ&pub=1",
      "query":"SELECT A,D WHERE D > 100 ORDER BY D",
      "refreshInterval": 5,
      "chartType": "Table",
      "options": {
        "alternatingRowStyle": true,
        "showRowNumber" : true
      }
   });
 }
google.charts.setOnLoadCallback(drawVisualization);
</script>

This next example creates the same table, but creates a DataTable locally:

<script type='text/javascript'>
  google.charts.load('current');
  function drawVisualization() {
    var dataTable = [
      ["Country", "Population Density"],
      ["Indonesia", 117],
      ["China", 137],
      ["Nigeria", 142],
      ["Pakistan", 198],
      ["India", 336],
      ["Japan", 339],
      ["Bangladesh", 1045]
    ];
    google.visualization.drawChart({
      "containerId": "visualization_div",
      "dataTable": dataTable,
      "refreshInterval": 5,
      "chartType": "Table",
      "options": {
        "alternatingRowStyle": true,
        "showRowNumber" : true,
      }
    });
  }
  google.charts.setOnLoadCallback(drawVisualization);
</script>

This example passes in a JSON string representation of the chart, which you might have loaded from a file:

<script type="text/javascript">
  google.charts.load('current');
  var myStoredString = '{"containerId": "visualization_div",' +
    '"dataSourceUrl": "https://spreadsheets.google.com/a/google.com/tq?key=pCQbetd-CptGXxxQIG7VFIQ&pub=1",' +
    '"query":"SELECT A,D WHERE D > 100 ORDER BY D",' +
    '"refreshInterval": 5,' +
    '"chartType": "Table",' +
    '"options": {' +
    '   "alternatingRowStyle": true,' +
    '   "showRowNumber" : true' +
    '}' +
  '}';
  function drawVisualization() {
    google.visualization.drawChart(myStoredString);
  }
  google.charts.setOnLoadCallback(drawVisualization);
</script>

drawToolbar()

This is the constructor for the toolbar element that can be attached to many visualizations. This toolbar enables the user to export the visualization data into different formats, or to provide an embeddable version of the visualization for use in different places. See the toolbar page for more information and a code example.