> Fetch clean Markdown by appending `.md` to any page URL under https://signalwire.com/docs or requesting it with the HTTP header `Accept: text/markdown`. The root index at https://signalwire.com/docs/llms.txt lists the available documentation indexes.

# unset

> Unset specified variables.

Unset specified variables. The variables have been set either using the [`set`](/docs/swml/reference/calling/set) command
or as a byproduct of some other statements or methods (like [`record`](/docs/swml/reference/calling/record))

**`unset`** `string | string[]` — required

The name of the variable to unset (as a string) or an array of variable names to unset.

---

## **Variable**

Any variable can be unset by this method.

## **Examples**

### Unset a single variable

#### YAML

```yaml
version: 1.0.0
sections:
  main:
    - set:
        num_var: 1
    - play:
        url: 'say: The value of num_var is: ${num_var}.'
    - unset: num_var
    - play:
        url: 'say: The value of num_var is ${num_var}.'
```

#### JSON

```json
{
  "version": "1.0.0",
  "sections": {
    "main": [
      {
        "set": {
          "num_var": 1
        }
      },
      {
        "play": {
          "url": "say: The value of num_var is: ${num_var}."
        }
      },
      {
        "unset": "num_var"
      },
      {
        "play": {
          "url": "say: The value of num_var is ${num_var}."
        }
      }
    ]
  }
}
```

### Unset multiple variables

#### YAML

```yaml
version: 1.0.0
sections:
  main:
    - set:
        systems:
          hr:
            - tracy
            - luke
          engineering:
            john: absent
        name: john
    - play:
        url: 'say: ${systems.hr}'
    - unset:
        - systems
        - name
    # this play statement emits an error because `systems` is undefined
    # at this point so there's nothing for `play` to say.
    - play:
        url: 'say: ${systems}'
```

#### JSON

```json
{
  "version": "1.0.0",
  "sections": {
    "main": [
      {
        "set": {
          "systems": {
            "hr": [
              "tracy",
              "luke"
            ],
            "engineering": {
              "john": "absent"
            }
          },
          "name": "john"
        }
      },
      {
        "play": {
          "url": "say: ${systems.hr}"
        }
      },
      {
        "unset": [
          "systems",
          "name"
        ]
      },
      {
        "play": {
          "url": "say: ${systems}"
        }
      }
    ]
  }
}
```

## **See Also**

* **[Variables and Expressions](/docs/swml/reference/variables)**: Complete reference for SWML variables, scopes, and syntax
* **[set](/docs/swml/reference/calling/set)**: Set variables in the script

> Unset specified variables.