django variable to javascript

Question

I'm trying to use google charts to visualize some data. As described in docs, i put this code to my template:

<script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
<script type="text/javascript">
  google.charts.load('current', {'packages':['corechart']});
  google.charts.setOnLoadCallback(drawChart);

  function drawChart() {
    var tmp = document.getElementById('result').value;
    var data = google.visualization.arrayToDataTable([
      ['Year', 'Sales', 'Expenses'],
      ['2004',  1000,      400],
      ['2005',  1170,      460],
      ['2006',  660,       1120],
      ['2007',  1030,      540]]
    );

    var options = {
      title: 'Company Performance',
      curveType: 'function',
      legend: { position: 'bottom' }
    };

    var chart = new google.visualization.LineChart(document.getElementById('curve_chart'));

    chart.draw(data, options);
  }
</script>
<div id="curve_chart" style="width: 900px; height: 500px"></div>

And it works fine. But i need to pass some custom data, so i did:

views.py:

def home(request): 
    example = [
      ['Year', 'Sales', 'Expenses'],
      ['2004',  1000,      400],
      ['2005',  1170,      460],
      ['2006',  660,       1120],
      ['2007',  1030,      540]
    ]
    return render(request, 'home.html', {'example': example})

As example data i used the same array. Next i replaced array in javascript code to {{ example }}:

 var data = google.visualization.arrayToDataTable( {{example}} );

And nothing happens. Google chart isn't drawing on my webpage anymore.
What im doing wrong? Also i tried to use json.dumps in python code and it didn't worked for me.

YPCrumble · Accepted Answer · 2016-06-19 08:47:25Z

1

You should simply turn your list of lists into valid json before you pass it to the template:

import json

def home(request): 
    example = [
      ['Year', 'Sales', 'Expenses'],
      ['2004',  1000,      400],
      ['2005',  1170,      460],
      ['2006',  660,       1120],
      ['2007',  1030,      540]
    ]
    example = json.dumps(example)
    return render(request, 'home.html', {'example': example})

Make sure you're using the safe template tag:

var data = google.visualization.arrayToDataTable( {{example|safe}} );

What is the error you're getting when you try that?

edited Jun 19, 2016 at 8:47

answered Jun 19, 2016 at 8:39

YPCrumble

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1 Comment

Mental Over a year ago

Ok, i tried it too, and tried to use JSON.parse() method in javascript but nothing. Well, the key is filter safe thats the answer, thanks!

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