CODEWITHSUNDEEP
djangodjango-templates
Prof. Falken
Prof. Falken

Reputation: 549

Django Templates: Writing an if filter to get around dividing by Zero

I am using template tags to divide two numbers. The problem occurs when the denominator is zero. I am trying to use if with operators but this seems to not be working.

<td class="data">${% if nnl_asof_mtdgoal %}{{ nl_mtdgoal.get_mtd_newloansgoal|div:nnl_asof_mtdgoal.get_mtd_numnewloansgoals |floatformat:"2"| intcomma }}{% endif %}

This gives me this error

File "C:\pycharm-virtenv\DjangoPostgres\lib\site-packages\mathfilters\templatetags\mathfilters.py" in div
  72.         return nvalue / narg

Exception Type: ZeroDivisionError at /reports/goals/
Exception Value: float division by zero

As it should since its division by zero. When I try this:

<td class="data">${% if nnl_asof_mtdgoal !="0" %}{{ nl_mtdgoal.get_mtd_newloansgoal|div:nnl_asof_mtdgoal.get_mtd_numnewloansgoals |floatformat:"2"| intcomma }}{% endif %}
                    </td>

I get this error:

Exception Type: TemplateSyntaxError at /reports/goals/
Exception Value: Could not parse the remainder: '!="0"' from '!="0"'

I know this has to be an easy one but I cannot seem to figure out how to only draw the table if the division is True, i.e. not dividing by zero.

Upvotes: 0

Views: 857

Answers (1)

Alasdair
Alasdair

Reputation: 308829

You need a space after != in your template tag, i.e.

{% if nnl_asof_mtdgoal != "0" %}

If nnl_asof_mtdgoal was an integer and not a string, you would do:

{% if nnl_asof_mtdgoal != 0 %}

Since you use div:nnl_asof_mtdgoal.get_mtd_numnewloansgoals in your template, it looks as if nnl_asof_mtdgoal is not an integer, so you should change the check to:

{% if nnl_asof_mtdgoal.get_mtd_numnewloansgoals != 0 %}

Note that Django encourages you to keep logic out of the templates. It might be better to try to shift the calculation (and checking for zero) to the view.

Upvotes: 2

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