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Django template how to look up a dictionary value with a variable

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Chapters
00:00 Django Template How To Look Up A Dictionary Value With A Variable
00:29 Answer 1 Score 50
01:12 Accepted Answer Score 470
01:33 Answer 3 Score 97
01:52 Answer 4 Score 8
02:09 Thank you

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Full question
https://stackoverflow.com/questions/8000...

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Content licensed under CC BY-SA
https://meta.stackexchange.com/help/lice...

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Tags
#python #django #templates #dictionary

#avk47



ACCEPTED ANSWER

Score 470


Write a custom template filter:

from django.template.defaulttags import register
...
@register.filter
def get_item(dictionary, key):
    return dictionary.get(key)

(I use .get so that if the key is absent, it returns none. If you do dictionary[key] it will raise a KeyError then.)

usage:

{{ mydict|get_item:item.NAME }}



ANSWER 2

Score 97


Fetch both the key and the value from the dictionary in the loop:

{% for key, value in mydict.items %}
    {{ value }}
{% endfor %}

I find this easier to read and it avoids the need for special coding. I usually need the key and the value inside the loop anyway.




ANSWER 3

Score 50


You can't by default. The dot is the separator / trigger for attribute lookup / key lookup / slice.

Dots have a special meaning in template rendering. A dot in a variable name signifies a lookup. Specifically, when the template system encounters a dot in a variable name, it tries the following lookups, in this order:

  • Dictionary lookup. Example: foo["bar"]
  • Attribute lookup. Example: foo.bar
  • List-index lookup. Example: foo[bar]

But you can make a filter which lets you pass in an argument:

https://docs.djangoproject.com/en/dev/howto/custom-template-tags/#writing-custom-template-filters

@register.filter(name='lookup')
def lookup(value, arg):
    return value[arg]

{{ mydict|lookup:item.name }}



ANSWER 4

Score 8


For me creating a python file named template_filters.py in my App with below content did the job

# coding=utf-8
from django.template.base import Library

register = Library()


@register.filter
def get_item(dictionary, key):
    return dictionary.get(key)

usage is like what culebrón said :

{{ mydict|get_item:item.NAME }}