Possible to merge arrays using their values as keys?

[kyguy]

Is it possible to merge arrays using values as keys?

x1.yaml

x:
  - a
  - b

x2.yaml

x:
  - b
  - c

We can merge arrays using their indices as keys:

yq ea 'select(fi==0) *d select(fi==1)' x1.yaml x2.yaml

x:
  - b
  - c

But is there a way to merge arrays using their values as keys in order to remove duplicate values?

x:
  - a
  - b
  - c

[mikefarah]

You should be able to do it - I've recently added an example of merging arrays using matching object keys:

https://mikefarah.gitbook.io/yq/operators/multiply-merge#merge-arrays-of-objects-together-matching-on-a-key

[mikefarah]

Looks like all you'd need to do is drop the '.a' bit in the select (so i think it would be select(. == $cur)

[kyguy]

Thanks for the example, I appreciate it!

I tried dropping the '.a' in the select statement

yq eval-all '(select(fi==1) | .[]) as $two | select(fi==0) | .[] |= (. as $cur |  $cur * ($two | select(. == $cur)))' x1.yaml x2.yaml

and got the following output:

x:
  - a
  - b

Since we are working with array values I think we need to splat the input we pass to the select statement, but I am still trying to find the right combination to get the select statement working on the array values. Once I find it l will post it here. Thanks again for your help!

[mikefarah]

In v4.9.0+ I added a unique operator so you can:

yq ea 'select(fi==0).x = (select(fi==0).x + select(fi==1).x | unique) | select(fi==0)' data1.yml data2.yml

[kyguy]

Wow, this is awesome! I was having trouble getting it right before but this new feature makes it super easy! Thank you so much for your help!