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PONewbie: Django : Adding calculated results to Queryset before passing to template
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copied!<p>Its day two of my new life with Django, please excuse the simplicity of my question.</p> <p>I have an existing DB table(read-only access) that I have successfully displayed the contents of on a webpage using urls, views, models and all that good stuff.</p> <p>The challenge I have is the table does not contain all the information I need to display. The table contains test results with the columns, sampletime, samplevalue, sampleresult. I need to display different data based on what I calculate from those columns.</p> <p>My end goal is to display this info as a time series graph using <a href="http://code.google.com/p/flotr/" rel="noreferrer">flotr</a>. For now Id be happy to just dump the data I need to a table on a web page.(So I can visualize the resulting data)</p> <p>What Id like to pass to the template is,</p> <ul> <li>jssampletime(the sampletime datetime object converted to javascript epoch ms)</li> <li>resultvalue(rolling sum+- of samplevalue based on whether sampleresult was good or bad)</li> </ul> <p>I'm fine with creating jssampletime and resultvalue using def functions. I presume I would add these functions to views.py</p> <p>I guess what I need to do iterate over the a querySet in views.py and store the results in a list of dictionaries which I pass to the template. Something like this(code not tested).</p> <p>views.py</p> <pre><code># views.py # Sudo code to assit in asking the question from django.shortcuts import render_to_response from thing.reporter.models import Samples def _datetime_to_js(sampletime): #.. date conversion epoch magic return jsd_result def _rolling_sum(samplevalue,sampleresult): #.. summing magic return sum_result def dumptable(request): # The def that is called by urls.py object_list = Samples.objects.all() list_for_template = [] for row in object_list: jssampletime = _datetime_to_js(row.sampletime) resultvalue = _rolling_sum(row.samplevalue,row.sampleresult) list_for_template.append({'jssampletime':jssampletime,'resultvalue':resultvalue}) return render_to_response('tabledump.html', {'result_list': list_for_template}) </code></pre> <p>tabledump.html</p> <pre><code># tabledump.html template {% block content %} <h2>Results dumped to page for testing</h2> <ul> <table> {% for result in result_list %} <tr> <td>{{ result.jssampletime }}</td> <td>{{ result.resultvalue }}</td> </tr> {% endfor %} </table> </ul> {% endblock %} </code></pre> <p>I think this would work but Im not sure if it is the Django MVC way.</p> <p>Is it right that I,</p> <ul> <li>calculate the result I need in views.py by interating over a queryset result?</li> <li>pass my result to a template as a list of dict(is a queryset more than that)?</li> </ul> <p>I guess Im looking for some direction and code tips. Am I on the right path ? Is there a better way ?</p>

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