Unique

This is used to filter out duplicated items in an array. Note that the original order of the array is maintained.

Unique array of scalars (string/numbers)

Note that unique maintains the original order of the array.

Given a sample.yml file of:

[2, 1, 3, 2]

then

yq 'unique' sample.yml

will output

[2, 1, 3]

Unique works on the node value, so it considers different representations of nulls to be different

Given a sample.yml file of:

[~, null, ~, null]

then

yq 'unique' sample.yml

will output

[~, null]

Run against the node tag to unique all the nulls

Given a sample.yml file of:

[~, null, ~, null]

then

yq 'unique_by(tag)' sample.yml

will output

[~]

Given a sample.yml file of:

[{name: harry, pet: cat}, {name: billy, pet: dog}, {name: harry, pet: dog}]

then

yq 'unique_by(.name)' sample.yml

will output

[{name: harry, pet: cat}, {name: billy, pet: dog}]