How to Get Values from Dictionary in Jinja When Key Is a Variable?
I'm Trying to Retrieve Entries from a Python Dictionary in Jinja2, but the Problem Is I Don't Know What Key I Want to Access Ahead of Time - the Key Is Stored...
I'm trying to retrieve entries from a python dictionary in jinja2, but the problem is I don't know what key I want to access ahead of time - the key is stored in a variable called s.course. So my problem is I need to double-substitute this variable. I don't want to use a for loop because that will go through the dictionary way more than is necessary. Here's a workaround that I created, but it's possible that the s.course values could change so obviously hard-coding them like this is bad. I want it to work essentially like this:
{% if s.course == "p11" %}
{{course_codes.p11}}
{% elif s.course == "m12a" %}
{{course_codes.m12a}}
{% elif s.course == "m12b" %}
{{course_codes.m12b}}
{% endif %}
But I want it to look like this:
{{course_codes.{{s.course}}}}
Thanks!
3 Answers
You can use course_codes.get(s.course):
>>> import jinja2
>>> env = jinja2.Environment()
>>> t = env.from_string('{{ codes.get(mycode) }}')
>>> t.generate(codes={'a': '123'}, mycode='a').next()
u'123'
There is no need to use the dot notation at all, you can do:
"{{course_codes[s.course]}}"
I'm using Jinja with Salt, and I've found that something like the following works well:
{% for role in pillar.packages %}
{% for package in pillar['packages'][role] %}
install_{{ package }}:
pkg.installed:
- name: {{ package }}
{% endfor %}
{% endfor %}
That is, use the more verbose [ ] syntax and leave the quotes out when you need to use a variable.
Elena Rostova holds a Master's degree in Public Health Journalism. She covers groundbreaking medical research, holistic wellness trends, mental health awareness, and nutritional science.
