Django template ifequal comparison of decimals

Question

So, I have a decimalfield that can be 3 different values. In my view, I pass in a dictionary of values that contains the appropriate decimal values as keys.

{% for item in booklist %}  
    {% for key, value in numvec.items %}  
        {{item.number}}  
        {% ifequals item.number {{key}} %}  
            {{value}}  
        {% endifequals %}  
    {% endfor %}
{% endfor %}

this is the dict I pass in as numvec:

numvec = {"TEST":Decimal("0.999"), "TEST2":Decimal("0.500"),

"TEST3":Decimal("0.255")}

the number field was defined as having these choices in my model:

BOOK_CHOICES=((Decimal("0.999"), 'TEST'),(Decimal("0.500"), 'TEST2'),(Decimal("0.255"), 'TEST3'),)

The item number prints out just fine in the view if I compare the dict with the attribute, but for some reason the ifequals cannot properly compare two decimals together. Is this a bug, or am I doing something wrong in my template with ifequals?

Answer 1

According to this, it seems you can only compare strings. I'd make my own template tag if I were you.

Answer 2

Simplest solution is to define a method on the model which encapsulates the numeric logic and returns the human-friendly string.

Or you can write a template tag to do it, which is a lot more code, but perhaps preserves the model/view layer separation a bit better.

Answer 3

It's not quite clear if this would help Ardesco but there is template_utils which has if_greater, if_greater_or_equal, if_less, if_less_or_equal tags (among others) which solve very related cases where a plain ifequals isn't quite enough.

after installing just add template_utils do your django settings.py under INSTALLED_APPS and then put {% load comparison %} in your template

Answer 4

It is not a bug and it is possible to achieve what you're trying to do.

However, first of all few remarks about your code:

• There is no "ifequals/endifequals" operator. You either use "ifequal/endifequal" or "if/endif".
• Second thing. Your code {% ifequal item.number {{key}} %} would cause TemplateSyntaxError Exception if you leave double curly brackets inside the "ifequal" or "if" operator.

Now the solution:

1. Just simply use "stringformat" filter to convert your decimal values to string.
2. Skip curly brackets when you use variables inside operators.
3. Don't forget that variable inside an "if" or "ifequal" operator is always represented as a string.

Here is an example:

{% for item in decimals %}  
  {% if item|stringformat:"s" == variable %}  
    {{ variable }}
  {% endif %}  
{% endfor %}

Answer 5

The solution:

{% for item in decimals %}  
  {% if item|stringformat:"s" == variable %}  
    {{ variable }}
  {% endif %}  
{% endfor %}

works well for comparing a decimal (like the loop) to a string (like a passed value)