Django Template String Concatenation based on number of non-empty variables

Question

I have two string variables that I want to display on a Django template. If variable a is empty, do not display it. Similar with b. But if a and b are both non-empty, then concatenate the two strings with a ' & '.

Here's the logic in Python.

res = ''
if a != '':
    res = a

if b != '':
    if res == '':
        res = b
    else:
        res = res + ' & ' + b

print(res)

How would I write this logic into a Django template?

Answer 1

you should write this logic in view as the comment of @ruddra, but if you adhere to use django template, you can try this:

{% if a == ' ' %}
    {% if b == ' ' %}
        res = ''
    {% else %}
        res = {{b}}
    {% endif %}
{% else %}
    {% if b == ' ' %}
        res = {{a}}
    {% else %}
        res = {{a}} & {{b}}
    {% endif %}
{% endif %}

Answer 2

As others have pointed out, it's easier to write this in your view instead of template .

If you really want to:

{% if a != '' and b != '' %}
  {{ a }}&{{ b }}
{% elif a != '' and b == '' %}
  {{ a }}
{% elif a == '' and b != '' %}
  {{ b }}
{% else %}
  {# You didn't mention #}
{% endif %}

Answer 3

res=''
if a !='': 
     if b!='':
          res= a + '&' + b     
     else:
          print('b is empty')
else:
     print('a is empty')

print(res)

if 'res' is empty its print nothing