# is_list · FT4 Rell API · Chromia Docs (concept)

> function is_ list(gtv: gtv): boolean Used to check if a gtv value is encoding a list Parameters gtv — the value to check

Source: https://docs.chromia.com/pages/ft4-rell/-f-t4-library/lib.ft4.utils/is_list/

FUNCTION

# is\_list

```signature
function is_list(gtv: gtv): boolean
```

[Source](https://gitlab.com/chromaway/ft4-lib/-/blob/development/rell/src/lib/ft4/utils/utils.rell#lines-260)

Used to check if a gtv value is encoding a `list`

**Parameters**

* **gtv** — the value to check

[View this page on docs.chromia.com](https://docs.chromia.com/pages/ft4-rell/-f-t4%20-library/lib.ft4.utils/is_list.html)Generated API reference, mirrored from the live docs