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POTransforming data in Django. Want to be able to apply sums to a decimal field
 

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  1. POTransforming data in Django. Want to be able to apply sums to a decimal field
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    <p>I have a model like this.</p> <pre><code>#models.py class Payment(models.Model): unit_price = models.DecimalField(max_digits=12, decimal_places=2) discount = models.DecimalField(max_digits=12, decimal_places=2) payment_terms = models.CharField(max_length=80) amount = models.DecimalField(max_digits=12, decimal_places=2) VAT = models.DecimalField(max_digits=4, decimal_places=2) def __unicode__(self): return unicode(self.unit_price) class Invoice(models.Model): client = models.ForeignKey(Client) payment = models.ForeignKey(Payment) date = models.DateField() invoice_no = models.CharField(max_length=16) work_orders = models.ManyToManyField(Work_Order) contract_info = models.ForeignKey(Contract_Info) def __unicode__(self): return self.invoice_no </code></pre> <p>What I want to focus is payment so try forgetting everything else. Here is my views.py.</p> <pre><code>#views.py @login_required def invoice_details(request, id=1): invoices_list = Invoice.objects.filter(pk=id) invoice = get_object_or_404(Invoice, pk=id) client = invoices_list[0].client work_orders = invoices_list[0].work_orders payment = invoices_list[0].payment return render_to_response(('invoice_details.html', locals()), {'work_orders': work_orders,'payment':payment,'client': client, 'invoice': invoice ,'invoices_list': invoices_list}, context_instance=RequestContext(request)) </code></pre> <p>And here is my template.</p> <pre><code>&lt;h1&gt;invoice_details.html&lt;h1&gt; {{ payment.amount }} </code></pre> <p>The template displays the payment amount in a decimal value. What I want to be able to do is some sums with {{payment.amount}}. Suppose if I wanted to multiply whatever the value<br> {{payment.amount}} by let say 2. How would I do this? </p>
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    1. USShehzad009
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    1. COWhy are you doing a `.filter()` just to index it, when you do a very similar operation on the very next line?
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      1. POTransforming data in Django. Want to be able to apply sums to a decimal field
      1. USIgnacio Vazquez-Abrams
    2. COI know. never mind about that.
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    3. COWhy do you want to do that in the template?
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      1. POTransforming data in Django. Want to be able to apply sums to a decimal field
      1. USAndré Caron
 

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