yq/operators/create-collect-into-object.md

# Create, Collect into Object

This is used to construct objects (or maps). This can be used against existing yaml, or to create fresh yaml documents.

## Collect empty object

Running

```bash
yq eval --null-input '{}'
```

will output

```yaml
{}
```

## Wrap (prefix) existing object

Given a sample.yml file of:

```yaml
name: Mike
```

then

```bash
yq eval '{"wrap": .}' sample.yml
```

will output

```yaml
wrap:
  name: Mike
```

## Using splat to create multiple objects

Given a sample.yml file of:

```yaml
name: Mike
pets:
  - cat
  - dog
```

then

```bash
yq eval '{.name: .pets.[]}' sample.yml
```

will output

```yaml
Mike: cat
Mike: dog
```

## Working with multiple documents

Given a sample.yml file of:

```yaml
name: Mike
pets:
  - cat
  - dog
---
name: Rosey
pets:
  - monkey
  - sheep
```

then

```bash
yq eval '{.name: .pets.[]}' sample.yml
```

will output

```yaml
Mike: cat
Mike: dog
Rosey: monkey
Rosey: sheep
```

## Creating yaml from scratch

Running

```bash
yq eval --null-input '{"wrap": "frog"}'
```

will output

```yaml
wrap: frog
```