# list.index_of · Rell standard library · Chromia Docs (concept)

> pure function index_ of(value: T): integer Search for the first occurrence of the specified element within this list. Parameters value — the element for wh

Source: https://docs.chromia.com/pages/rell-stdlib/-rell-system-library/root/list/index_of/

FUNCTION

# list.index\_of

```signature
pure function index_of(value: T): integer
```

Search for the first occurrence of the specified element within this list.

**Parameters**

* **value** — the element for which to search

**Returns**

the index of the first occurrence of the element within this list, or `-1` if the element
does not occur in this list

Since 0.9.0

[View this page on docs.chromia.com](https://docs.chromia.com/pages/rell-stdlib/-rell%20-system%20-library/%5Broot%5D/list/index_of.html)Generated API reference, mirrored from the live docs