pass 2d array from ruby to javascript

Question

I want to pass a 2d array from ruby to javascript.

I currently have this id in the view:

 <script type="text/javascript" src="https://www.google.com/jsapi"></script>
 <script type="text/javascript">
 google.load("visualization", "1", {packages:["corechart"]});
 google.setOnLoadCallback(drawChart);
 function drawChart() {
 var data = google.visualization.arrayToDataTable(<%= @statistics %>);
 var options = {
 title: 'My Daily Activities'
 };
 var chart = new google.visualization.PieChart(document.getElementById('chart_div'));
 chart.draw(data, options);
 }
 </script>
<div id="chart_div" style="width: 900px; height: 500px;"></div>

@statistics is a 2d array comin from the controller

Answer 1

The method you are looking for is #to_json.

var data = google.visualization.arrayToDataTable(<%= @statistics.to_json %>);

For example:

[["abc", 123], ["def", 456]].to_json # => [["abc",123],["def",456]]
[[1, 2], [3, 4], [5, 6]].to_json # => [[1,2],[3,4],[5,6]]

If your @statistics variable is not a plain 2D array, it may require additional processing before you output it to JSON.

• HeshamW: It does not work, It gives me a blank page. My array should be something like that : [['task', 'points'], ['A', 20]]
• Benjamin Manns: What is the code that generates your @statistics array? If you run the code in your rails console, what is the output?
• HeshamW: I just have this in the console : @statistics = [['task', 'points'], ['A', 20]]
• Benjamin Manns: [['task', 'points'], ['A', 20]].to_json gives me [["task","points"],["A",20]], so it looks like there is something else going on. Can you post the exact controller and view code you are using?