Counting elements in a sequence
The community.general.counter filter plugin allows you to count (hashable) elements in a sequence. Elements are returned as dictionary keys and their counts are stored as dictionary values.
- name: Count character occurrences in a string
debug:
msg: "{{ 'abccbaabca' | community.general.counter }}"
- name: Count items in a list
debug:
msg: "{{ ['car', 'car', 'bike', 'plane', 'bike'] | community.general.counter }}"
This produces:
TASK [Count character occurrences in a string] ********************************************
ok: [localhost] => {
"msg": {
"a": 4,
"b": 3,
"c": 3
}
}
TASK [Count items in a list] **************************************************************
ok: [localhost] => {
"msg": {
"bike": 2,
"car": 2,
"plane": 1
}
}
This plugin is useful for selecting resources based on current allocation:
- name: Get ID of SCSI controller(s) with less than 4 disks attached and choose the one with the least disks
debug:
msg: >-
{{
( disks | dict2items | map(attribute='value.adapter') | list
| community.general.counter | dict2items
| rejectattr('value', '>=', 4) | sort(attribute='value') | first
).key
}}
vars:
disks:
sda:
adapter: scsi_1
sdb:
adapter: scsi_1
sdc:
adapter: scsi_1
sdd:
adapter: scsi_1
sde:
adapter: scsi_2
sdf:
adapter: scsi_3
sdg:
adapter: scsi_3
This produces:
TASK [Get ID of SCSI controller(s) with less than 4 disks attached and choose the one with the least disks]
ok: [localhost] => {
"msg": "scsi_2"
}
New in version 4.3.0.