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POHow do I pass a Ruby array to Javascript to make a line graph
 

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  1. POHow do I pass a Ruby array to Javascript to make a line graph
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    <p>I am trying to make a webpage to display line graphs in my Ruby on Rails 2.3.14 application. I found a tool, called JS Charts, which allows me to create nice graphs using Javascript, but I am having trouble sending it the data it needs. Here is the way to make a static line graph:</p> <pre><code>&lt;script type="text/javascript"&gt; var myData = new Array([1, 395], [2, 244], [3, 223], [4, 210], [5, 238], [6, 223], [7, 275], [8, 31]); var myChart = new JSChart('chartcontainer', 'line'); myChart.setDataArray(myData); myChart.draw(); &lt;/script&gt; </code></pre> <p>I put that code into stats.html.erb, and it shows up. However, I need it to display line graph data that I provide it. A 2 dimensional array is created in the controller:</p> <pre><code>&gt;&gt; @a =&gt; [[1, 395], [2, 244], [3, 223], [4, 210], [5, 238], [6, 223], [7, 275], [8, 31]] </code></pre> <p>I should be able to use that variable in the view, and set <code>var myData</code> to it, with something like:</p> <pre><code>var myData = "&lt;%= @a %&gt;"; </code></pre> <p>I tried other things like:</p> <pre><code>var myData = JSON.parse( "&lt;%= @a.to_json %&gt;" ); </code></pre> <p>but nothing seems to work. Is there anything I can do?</p> <p>EDIT:</p> <p>There was an issue with the array the controller passed into the view (@a), which was empty. I was able to use:</p> <pre><code>var myData = JSON.parse( "&lt;%= @a.to_json %&gt;" ); </code></pre> <p>to display the line graph with the right data being passed into the view.</p>
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    1. COGood question. I'm not sure why your examples aren't working, assuming that you're in a .erb file and the ruby interpolation can work. Maybe try interpolating to a string? IE `<%= @.to_s %>`, because the javascript is going to evaluate what ruby injects into the script as though you had typed it in...
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    2. CO@eric paste the generated html of the result page.
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    3. COWait, somehow it worked this time. I think there was an issue with the data the controller passed into the view (`@a`). I used `JSON.parse( "<%= @a.to_json %>" );`. I appreciate the responses at least.
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