yq/pkg/yqlib/doc/operators/entries.md

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# Entries
Similar to the same named functions in `jq` these functions convert to/from an object and an array of key-value pairs. This is most useful for performing operations on keys of maps.
## to_entries Map
Given a sample.yml file of:
```yaml
a: 1
b: 2
```
then
```bash
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yq 'to_entries' sample.yml
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```
will output
```yaml
- key: a
value: 1
- key: b
value: 2
```
## to_entries Array
Given a sample.yml file of:
```yaml
- a
- b
```
then
```bash
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yq 'to_entries' sample.yml
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```
will output
```yaml
- key: 0
value: a
- key: 1
value: b
```
## to_entries null
Given a sample.yml file of:
```yaml
null
```
then
```bash
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yq 'to_entries' sample.yml
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```
will output
```yaml
```
## from_entries map
Given a sample.yml file of:
```yaml
a: 1
b: 2
```
then
```bash
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yq 'to_entries | from_entries' sample.yml
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```
will output
```yaml
a: 1
b: 2
```
## from_entries with numeric key indices
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from_entries always creates a map, even for numeric keys
Given a sample.yml file of:
```yaml
- a
- b
```
then
```bash
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yq 'to_entries | from_entries' sample.yml
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```
will output
```yaml
0: a
1: b
```
## Use with_entries to update keys
Given a sample.yml file of:
```yaml
a: 1
b: 2
```
then
```bash
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yq 'with_entries(.key |= "KEY_" + .)' sample.yml
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```
will output
```yaml
KEY_a: 1
KEY_b: 2
```
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## Custom sort map keys
Use to_entries to convert to an array of key/value pairs, sort the array using sort/sort_by/etc, and convert it back.
Given a sample.yml file of:
```yaml
a: 1
c: 3
b: 2
```
then
```bash
yq 'to_entries | sort_by(.key) | reverse | from_entries' sample.yml
```
will output
```yaml
c: 3
b: 2
a: 1
```
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## Use with_entries to filter the map
Given a sample.yml file of:
```yaml
a:
b: bird
c:
d: dog
```
then
```bash
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yq 'with_entries(select(.value | has("b")))' sample.yml
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```
will output
```yaml
a:
b: bird
```