How to filter list by dictionary value in yq?

Question

I'm using https://mikefarah.gitbook.io/yq/ . How can I filter a list of dictionaries by a particular value in a list under a particular key? In the example below I want to filter the layouts list by condition "iso3166 list contains value 'GB'".

Example

Yaml output (condensed) from xkbcli list with one model and three layouts

models:
- name: pc86
  vendor: Generic
  description: Generic 86-key PC

layouts:
- layout: 'ch'
  variant: ''
  brief: 'de'
  description: German (Switzerland)
  iso639: ['deu', 'gsw']
  iso3166: ['CH']
- layout: 'gb'
  variant: 'gla'
  brief: 'gd'
  description: Scottish Gaelic
  iso639: ['eng', 'gla']
  iso3166: ['GB', 'CA']
- layout: 'gb'
  variant: 'colemak'
  brief: 'en'
  description: English (UK, Colemak)
  iso639: ['eng']
  iso3166: ['GB']

Desired output: the two 'GB' layouts

- layout: 'gb'
  variant: 'gla'
  brief: 'gd'
  description: Scottish Gaelic
  iso639: ['eng', 'gla']
  iso3166: ['GB', 'CA']
- layout: 'gb'
  variant: 'colemak'
  brief: 'en'
  description: English (UK, Colemak)
  iso639: ['eng']
  iso3166: ['GB']

So far I've tried yq ".layouts"

Answer 1

Use map and select.

# Selects by .layout
yq '.layouts | map(select(.layout == "gb"))'

# Selects by .iso3166[]
yq '.layouts | map(select(.iso3166[] == "GB"))'

- layout: 'gb'
  variant: 'gla'
  brief: 'gd'
  description: Scottish Gaelic
  iso639: ['eng', 'gla']
  iso3166: ['GB', 'CA']
- layout: 'gb'
  variant: 'colemak'
  brief: 'en'
  description: English (UK, Colemak)
  iso639: ['eng']
  iso3166: ['GB']