How to convert array of objects to csv?

[balki]

Consider below input yaml

❯ cat map.yaml                                                                                                                                           
foo: bar
items:
  - name: Tom
    species: cat
    color: blue
  - name: Jim
    species: dog
    color: brown

I want to convert it to below csv

name,species,color
Tom,cat,blue
Jim,dog,brown

I tried below and more - didn't work.

❯ cat map.yaml | yq '.items | @csv'           
Error: csv encoding only works for arrays of scalars (string/numbers/booleans), child[0] is a !!map
❯ cat map.yaml | yq '.items | values | @csv'
Error: 1:12: invalid input text "values | @csv"

I understand for csv to work, it has to be array of arrays like below,

❯ cat arr.yaml                     
foo: bar
items:
  - - Tom
    - cat
    - blue
  - - Jim
    - dog
    - brown
❯ cat arr.yaml | yq '.items | @csv'
Tom,cat,blue
Jim,dog,brown

No header but still ok. Is there a way to convert map.yaml to arr.yaml, so that it can be converted to csv?

[mikefarah]

Good question - I should update the guide with this example.

yq '[["name", "species", "color"]] + [.items[] | [.name, .species, .color]]' examples/data1.yaml -o=csv

name,species,color
Tom,cat,blue
Jim,dog,brown

[balki]

Thank you! Also got it to work without listing keys if each object has the same keys

❯ cat map.yaml | yq '[.items[0] | keys] + [.items[] | ([.*])]' -o=csv
name,species,color
Tom,cat,blue
Jim,dog,brown

❯ cat map.yaml | yq '.items | [.[0] | keys] + [(.[] | [.*])]' -o=csv
name,species,color
Tom,cat,blue
Jim,dog,brown

[mikefarah]

I've updated yq (v4.27.1) to natively support cases like this - so you you can just -o=csv and it'll work :)

See https://mikefarah.gitbook.io/yq/usage/csv-tsv#encode-array-of-objects-to-csv