Variable Operators

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Variable Operators

Like the jq equivalents, variables are sometimes required for the more complex expressions (or swapping values between fields).
Note that there is also an additional ref operator that holds a reference (instead of a copy) of the path, allowing you to make multiple changes to the same path.
Single value variable
Given a sample.yml file of:
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a: cat
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then
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yq eval '.a as $foo | $foo' sample.yml
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will output
1
cat
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Multi value variable
Given a sample.yml file of:
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- cat
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- dog
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then
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yq eval '.[] as $foo | $foo' sample.yml
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will output
1
cat
2
dog
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Using variables as a lookup
Example taken from jq​
Given a sample.yml file of:
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"posts":
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  - "title": Frist psot
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    "author": anon
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  - "title": A well-written article
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    "author": person1
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"realnames":
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  "anon": Anonymous Coward
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  "person1": Person McPherson
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then
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yq eval '.realnames as $names | .posts[] | {"title":.title, "author": $names[.author]}' sample.yml
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will output
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title: Frist psot
2
author: Anonymous Coward
3
title: A well-written article
4
author: Person McPherson
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Using variables to swap values
Given a sample.yml file of:
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a: a_value
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b: b_value
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then
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yq eval '.a as $x  | .b as $y | .b = $x | .a = $y' sample.yml
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will output
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a: b_value
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b: a_value
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Use ref to reference a path repeatedly
Note: You may find the with operator more useful.
Given a sample.yml file of:
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a:
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  b: thing
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  c: something
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then
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yq eval '.a.b ref $x | $x = "new" | $x style="double"' sample.yml
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will output
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a:
2
  b: "new"
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  c: something
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Unique

With

Last modified 2mo ago

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Contents

Single value variable

Multi value variable

Using variables as a lookup

Using variables to swap values

Use ref to reference a path repeatedly