Ansible loop over array

[Madushan Chathuranga]

Hi,

Is there a way to loop over an array in ansible with a given array size. eg: I have an array with 10 elements. I want to limit the iteration only to first 5 elemets.

Thanks.

[Karl Auer]

the slice() filter will give you a list of arrays each with one element in it

 (i.e., not what you were expecting, but still useful).

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Karl Auer

Email  : ka...@2pisoftware.com
Website: http://2pisoftware.com

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[eric.b....@nasa.gov]

Could you use an "indexed array" and use when to check for index <= 5?

https://docs.ansible.com/ansible/latest/user_guide/playbooks_loops.html#with-indexed-items

- name: with_indexed_items
  debug:
    msg: "Index {{ item.0 }} - Value {{ item.1 }}"
  with_indexed_items: "{{ items }}"

- name: with_indexed_items -> loop
  debug:
    msg: "{{ index }} - {{ item }}"
  loop: "{{ items|flatten(levels=1) }}"
  loop_control:
    index_var: index

[Brian Coca]

name: loop over first 5
debug: var=item
loop: "{{ mylist[:5] }}"

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Brian Coca

[Madushan Chathuranga]

@Brain Coca

That looks nice. Btw what if the number of elements available in the array is less than 5 and we give loop: "{{ mylist[:5] }}". Should that throw any exception?

[Brian Coca]

No, it will consume UP TO that number


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Brian Coca

[Madushan Chathuranga]

Thanks. I tried it out as well. In addition this degit no '5' will be an input from --extra-vars. eg : --extra-vars 'size=5'

then i was trying to consume that variable like this  loop: "{{ mylist[:size] }}" But this throws an error saying '' slice indices must be integers or none or have an __init__ method. is there a way that I can set this limit of the array using a variable?  

[Madushan Chathuranga]

UPDATE

a solution would be "{{size | int}}". I think when we pass it as an optional it take it as a string by default so using 'int' filter would solve this.

Thanks ,

Madushan

[Brian Coca]

cause size=5 is a string (k=v notation does not 'type' well),
mylist[:size|int] to avoid that or you can try yaml notation, but that
can also use type depending on circumstance, the |int at 'consumption'
is always safe.




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Brian Coca