yq/pkg/yqlib/doc/operators/has.md
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Markdown

# Has
This operation returns true if the key exists in a map (or index in an array), false otherwise.
## Has map key
Given a sample.yml file of:
```yaml
- a: yes
- a: ~
- a:
- b: nope
```
then
```bash
yq '.[] | has("a")' sample.yml
```
will output
```yaml
true
true
true
false
```
## Select, checking for existence of deep paths
Simply pipe in parent expressions into `has`
Given a sample.yml file of:
```yaml
- a:
b:
c: cat
- a:
b:
d: dog
```
then
```bash
yq '.[] | select(.a.b | has("c"))' sample.yml
```
will output
```yaml
a:
b:
c: cat
```
## Has array index
Given a sample.yml file of:
```yaml
- []
- [1]
- [1, 2]
- [1, null]
- [1, 2, 3]
```
then
```bash
yq '.[] | has(1)' sample.yml
```
will output
```yaml
false
false
true
true
true
```