Check if key exists in a Python dict in Jinja2 templates

Question

I have a python dictionary:

settings = {
   "foo" : "baz",
   "hello" : "world"
}

This variable settings is then available in the Jinja2 template.

I want to check if a key myProperty exists in the settings dict within my template, and if so take some action:

{% if settings.hasKey(myProperty) %}
   takeSomeAction();
{% endif %}

What is the equivalent of hasKey that I can use?

Just check: if settings[myproperty] is not None: I think this should work. — Prakash Kuma
– Prakash Kuma, Commented Jan 2, 2015 at 9:50

tshalif · Accepted Answer · 2016-01-17 14:59:20Z

200

Like Mihai and karelv have noted, this works:

{% if 'blabla' in item %}
  ...
{% endif %}

I get a 'dict object' has no attribute 'blabla' if I use {% if item.blabla %} and item does not contain a blabla key

answered Jan 17, 2016 at 14:59

tshalif

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4 Comments

chesterbr Over a year ago

Same for me. In my particular case I'm using Jinja2 inside Ansible.

Drew Over a year ago

Using jinja2 inside Ansible. Nothing helps. Both {% if 'blabla' in item %} and {% if item.blabla %} return the same 'dict object' has no attribute 'blabla' wtf???

blkpingu Over a year ago

argument of type 'StringField' is not iterable. Does not work for me

Seub Over a year ago

Is item supposed to be a dictionary in this answer? That's a confusing name (an item is a key/value pair inside a dictionary). Sorry if I'm missing something.

ma3oun · Accepted Answer · 2018-10-29 14:27:37Z

44

You can test for key definition this way:

{% if settings.property is defined %}

#...
{% endif %}

answered Oct 29, 2018 at 14:27

ma3oun

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3 Comments

Mayank Porwal Over a year ago

This looks like the correct way of checking if a key is present in dict or not. +1

Samha' Over a year ago

Your answer checks for object attributes, not dict keys.

s3dev Over a year ago

@Samha' - Dict objects can be accessed via the dot operator in Jinja2. While this appears to be accessing a property - it's a perfectly valid solution for testing for a dict key.

devinbost · Accepted Answer · 2019-03-22 14:50:33Z

15

This ~~works fine~~ doesn't work in cases involving dictionaries. In those cases, please see the answer by tshalif. Otherwise, with SaltStack (for example), you will get this error:

Unable to manage file: Jinja variable 'dict object' has no attribute '[attributeName]'

if you use this approach:

{% if settings.myProperty %}

note:
Will also skip, if settings.myProperty exists, but is evaluated as False (e.g. settings.myProperty = 0).

edited Mar 22, 2019 at 14:50

devinbost

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answered Jan 2, 2015 at 9:50

Mihai Zamfir

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9 Comments

Amal Antony Over a year ago

Can myProperty be a variable in the approach above?

Mihai Zamfir Over a year ago

Yes, a key in a dictionary. Is the equivalent of hasKey. And btw, hasKey is deprecated. Use in instead

karelv Over a year ago

when setting.myProperty exists, but it is equal to zero (integer 0) or to the boolean value False, this if test not for 'hasKey'. This means you need: {% if 'myProperty' in settings %}

ryantuck Over a year ago

this doesn't work for me (at least working with ansible). i found i needed {% if settings.myProperty is defined %}.

Florian Neumann Over a year ago

I don't get why this is accepted as answer - it throws an error if the dict is missing the key. Please correct the answer.

|

NFSpeedy · Accepted Answer · 2021-12-30 11:05:08Z

1

Actually, in the style of Python, if you do a simple if statement, it will work:

{% if settings.foo %}
Setting Foo: {{ settings.foo }}
{% endif %}
{% if settings.bar %}
Setting Bar: {{ settings.bar }}
{% endif %}
{% if settings.hello %}
Setting Hello: {{ settings.hello }}
{% endif %}

Output:

Setting Foo: baz
Setting Hello: world

Cheers!

answered Dec 30, 2021 at 11:05

NFSpeedy

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1 Comment

Marco Roy Over a year ago

This does not work to check if a key is set to false.

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