Jinja filters

Jinja filters allow you to run functions on some data right before it is rendered. It does not change the underlying data in anyway.

Quick introduction

• Filters are applied using the pipe | operator.
• You can chain multiple filters one after another to create a pipeline.
• Some filters requires arguments. Pass them in as if calling a function.

Lists

All filters that create Lists or work on Lists create Generator objects instead of Lists. To convert these objects back to Lists, use "list" filter at the end

Cheatsheet

String filters

Function		Example
upper, lower	Converts string to upper or lower case	apple | upper
replace(old, new, count=None)	Replaces all or a specified number of occurrences of the old substring with the new substring	apple | replace('a', 'b')
center(width=80)	Centers the text based on the given width. Note: there is no 'left' or 'right' filter. If you need to left or right align text, use format instead.
escape or e	converted into html safe sequence by sanitising '&', '<', '>', ‘ (singlequote), and ” (doublequote).
format(args)
indent(width=4, first=False, blank=False)	Indents text
capitalize	The first character of the string is uppercased	apple | capitalize
title	Uppercases every word
trim	Removes excess leading/trailing spaces
truncate(length=255, killwords=False, end='...', )	Truncates a string to the given length. Optionally specifies suffix if truncation happened.
wordwrap(width=79, break_long_words=True, wrapstring=None)	Line wraps the given text into a specified column width.

Iterables

Iterables include lists, tuples, strings, and dictionaries.

Function		Example
attr(name)
first / last / random	Selects the first / last / or random item
batch	Batches list items together	items = [1, 2, 3, 4, 5] items | batch(2, fill_with=8) | list Output: [ [1, 2], [3, 4], [5, 8 ] ]
slice	Slices a list into the given number of slices	items = [1, 2, 3, 4, 5] items | slice(2, fill_with=8) | list Output: [ [1, 2, 3], [4, 5, 8 ] ]
map(attribute=attributeName)		myDictList = [ {'a': 1, 'b': 2}, {'a': 3, 'b': 4}, {'a': 5, 'b': 6} ] myDictList | map(attribute='a') | list Output: [1, 3, 5]
map(filter)	Apply the given filter to every item in the list
reject(test) / select(test)	Removes or retains items that fail the test
rejectattr(attribute, test, args) selectattr(attribute, test, args)	Removes or retains items that have an attribute	myDict = ({'a': 0}, {'a': 1}, {'a': 2}) %} myDict | rejectattr('a', 'equalto', 1) | list Output: [{'a': 0}, {'a': 2}]
unique	returns all unique values
sort(reverse=False, case_sensitive=False, attribute=None)	sort
reverse	reverses order
shuffle	randomly orders the list

Data types

Function		Example
float(default) / int(default, base=10)
string	Converts to Unicode string
list	converts any iterable to a list
default(default='', bool=false)	Provides a default value if the value is undefined. If given bool is true, None or empty string will be treated as undefined.
filesizeformat	Converts to human readable sizes
from_json / json	Converts from json to a dictionary object or an object into json.
length / count	length of string or number of objects in a list

See also

• https://ansible-docs.readthedocs.io/zh/stable-2.0/rst/playbooks_filters.html#defaulting-undefined-variables