Extract last character of string with ansible and regex_replace filter

Question

In a playbook, I try to extract the last character of variable "ansible_hostname".

I try to use regex_replace filter to do that, but nothing works.

I simplified my piece of script with this ad-hoc command :

ansible localhost -m debug -a "msg= {{ 'devserver01' | regex_replace('[0-9]{1}$', '\1') }}"

I want to extract the last character : '1'.

I'm using Ansible 2.0.

It looks like you're correctly matching the last character `(\d)$` but then you are replacing `1` with itself, so no affect??? — micker, Jun 10 '16 at 12:27
If your goal is to JUST get the last character, you could just do `^.*(\d)$` and keep the `\1`. — micker, Jun 10 '16 at 12:31

score 24 · Accepted Answer · answered Jun 10 '16 at 12:32

24

Python can save the day, and is acceptable in this use.

Just add a [-1] to the end of the string or variable, which gets the last character in a string.

ansible localhost -m debug -a "msg={{ 'devserver01'[-1] }}"

answered Jun 10 '16 at 12:32

Theo

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Amol Damodar · Answer 2 · 2016-11-23T04:55:39.110

-1

The following will work for you.

ansible localhost -m debug -a "msg= {{ 'devserver01' | regex_replace('^(.+)([0-9]{1})$','\\1') }}"

Explanation:

^(.+) : it will take one or more group of characters from start
([0-9]{1})$ : removes one digit from end of string

\\1 : is a back reference to the first group

edited Nov 23 '16 at 04:55

answered Nov 23 '16 at 04:36

Amol Damodar

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Extract last character of string with ansible and regex_replace filter

2 Answers2