Ansible remove last character from string if its a number - ansible

Question

I have a list like the following
fruit: [ 'apple','orange2','grape3apple1']
I want an output like the following and want this to be stored in another var for further use
fruit_out: [ 'apple','orange','grape3apple' ]
If the last character is a number, I want the number stripped, if not, I need the string returned as is. I have looked around a bit without much luck getting any usable solution.

Answer 1

Reiterating my comment for context:
Given a string variable somevariable, somevariable[-1] is the last character, and somevariable[:-1] is the string not including the last character. –
I am looking for a validation to check if the last character is indeed a number. If there is a number at in the middle it should not count for the check
Ansible uses Python, so you can use any Python string method in your Ansible playbooks. For example, to have a task execute when a value ends with a number, you could write:
- debug:
msg: Your variable ends with a number!
when: somevariable[-1].isdigit()
You could perform the same check using a regular expression filter:
- debug:
msg: Your variable ends with a number!
when: somevariable is search('[0-9]$')

Answer 2

One possibility would be to use a regex and the filter regex_search.
So, given the task:
- debug:
msg: >-
{{
fruits
| map('regex_search', '^(.*?)[0-9]?$', '\1')
| map('first')
}}
vars:
fruits:
- apple
- orange2
- grape3apple1
This yields the expected:
ok: [localhost] =>
msg:
- apple
- orange
- grape3apple
The only tricky part in that regex is that you have to make your capturing group lazy, with the help of the lazy quantifier *?, otherwise your matched group will spawn over the unwanted number.

Answer 3

Use the filter regex_replace. For example, put the declarations below as appropriate
fruit: [apple, orange2, grape3apple1]
fruit_regex: '^(.+?)\d*$'
fruit_replace: '\1'
fruit_out: "{{ fruit|map('regex_replace', fruit_regex, fruit_replace)|list }}"
gives
fruit_out:
- apple
- orange
- grape3apple
Explanation of the regex
^ ....... matches the beginning of a string
(.+?) ... creates a capture group
. ... matches any character
+? ... 1 or more (append ? for non-greedy)
\d* ... digit, 0 or more
$ ....... matches the end of a string
Example of a complete playbook
- hosts: localhost
vars:
fruit: [apple, orange2, grape3apple1]
fruit_regex: '^(.+?)\d*$'
fruit_replace: '\1'
fruit_out: "{{ fruit|map('regex_replace', fruit_regex, fruit_replace)|list }}"
tasks:
- debug:
var: fruit_out