How to specify the key name when using to_entries

[tommyleedberg]

I'm relatively new to using the yq command and I would like to use `yq eval 'to_entries' to generate a new file from an existing one but when the new file is generated I'd like to change "key" to "name". I was able to get most of the way there I just can't figure out how to change the "key" properties name. I realize I could just do a string replace using sed but was wondering if there was a way to specify the key name in place.

I have the following:

Input file: temp.json

{
    "A": "first-letter",
    "B": "second-letter",
    "C": "third-letter"
}

Command:
yq eval -P 'to_entries | {"properties": .}' temp.json | cat > temp.yaml

This works as expected and I get the following result:

{
  "properties": [
    {
      "key": "A",
      "value": "first-letter"
    },
    {
      "key": "B",
      "value": "second-letter"
    },
    {
      "key": "C",
      "value": "third-letter"
    }
  ]
}

What I would like to get as an output is the following:

{
  "properties": [
    {
      "name": "A",
      "value": "first-letter"
    },
    {
      "name": "B",
      "value": "second-letter"
    },
    {
      "name": "C",
      "value": "third-letter"
    }
  ]
}

[mikefarah]

You can do it like this:

yq 'to_entries | (.[].key | key) = "name" | {"properties" : .}' examples/data1.yaml

The extra (.[].key | key) = "name" is basically saying:

• for each array element .[] match all the entries with a key named "key"
• This will return the value (e.g. "A") we want to update it's key, so we get (.[].key | key)
• Note that .key is referencing a map entry, named "key" whereas "key" (without the dot) is returning the key node of the value in the map.
• Now that we have the key node, we can update it.

Hope that makes sense!