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Adds documentation for all the regex filters (#28944)

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Fran Fitzpatrick 2017-09-01 19:12:15 -05:00 committed by scottb
parent 59787a3dbc
commit c51f2f835e
1 changed files with 42 additions and 24 deletions
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docs/docsite/rst/playbooks_filters.rst
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@ -643,6 +643,48 @@ The ``urlsplit`` filter extracts the fragment, hostname, netloc, password, path,
# }
Regular Expression Filters
``````````````````````````
To search a string with a regex, use the "regex_search" filter::
# search for "foo" in "foobar"
{{ 'foobar' | regex_search('(foo)') }}
# will return empty if it cannot find a match
{{ 'ansible' | regex_search('(foobar)') }}
To search for all occurrences of regex matches, use the "regex_findall" filter::
# Return a list of all IPv4 addresses in the string
{{ 'Some DNS servers are 8.8.8.8 and 8.8.4.4' | regex_findall('\b(?:[0-9]{1,3}\.){3}[0-9]{1,3}\b') }}
To replace text in a string with regex, use the "regex_replace" filter::
# convert "ansible" to "able"
{{ 'ansible' | regex_replace('^a.*i(.*)$', 'a\\1') }}
# convert "foobar" to "bar"
{{ 'foobar' | regex_replace('^f.*o(.*)$', '\\1') }}
# convert "localhost:80" to "localhost, 80" using named groups
{{ 'localhost:80' | regex_replace('^(?P<host>.+):(?P<port>\\d+)$', '\\g<host>, \\g<port>') }}
# convert "localhost:80" to "localhost"
{{ 'localhost:80' | regex_replace(':80') }}
.. note:: Prior to ansible 2.0, if "regex_replace" filter was used with variables inside YAML arguments (as opposed to simpler 'key=value' arguments),
then you needed to escape backreferences (e.g. ``\\1``) with 4 backslashes (``\\\\``) instead of 2 (``\\``).
.. versionadded:: 2.0
To escape special characters within a regex, use the "regex_escape" filter::
# convert '^f.*o(.*)$' to '\^f\.\*o\(\.\*\)\$'
{{ '^f.*o(.*)$' | regex_escape() }}
Other Useful Filters
````````````````````
@ -721,30 +763,6 @@ doesn't know it is a boolean value::
.. versionadded:: 1.6
To replace text in a string with regex, use the "regex_replace" filter::
# convert "ansible" to "able"
{{ 'ansible' | regex_replace('^a.*i(.*)$', 'a\\1') }}
# convert "foobar" to "bar"
{{ 'foobar' | regex_replace('^f.*o(.*)$', '\\1') }}
# convert "localhost:80" to "localhost, 80" using named groups
{{ 'localhost:80' | regex_replace('^(?P<host>.+):(?P<port>\\d+)$', '\\g<host>, \\g<port>') }}
# convert "localhost:80" to "localhost"
{{ 'localhost:80' | regex_replace(':80') }}
.. note:: Prior to ansible 2.0, if "regex_replace" filter was used with variables inside YAML arguments (as opposed to simpler 'key=value' arguments),
then you needed to escape backreferences (e.g. ``\\1``) with 4 backslashes (``\\\\``) instead of 2 (``\\``).
.. versionadded:: 2.0
To escape special characters within a regex, use the "regex_escape" filter::
# convert '^f.*o(.*)$' to '\^f\.\*o\(\.\*\)\$'
{{ '^f.*o(.*)$' | regex_escape() }}
To make use of one attribute from each item in a list of complex variables, use the "map" filter (see the `Jinja2 map() docs`_ for more)::
# get a comma-separated list of the mount points (e.g. "/,/mnt/stuff") on a host