| --- |
| page_title: index - Functions - Configuration Language |
| description: The index function finds the element index for a given value in a list. |
| --- |
| |
| # `index` Function |
| |
| `index` finds the first element index for a given value in a list. |
| |
| ```hcl |
| index(list, value) |
| ``` |
| |
| The returned index is zero-based. This function produces an error if the given |
| value is not present in the list. |
| |
| ## Examples |
| |
| ``` |
| > index(["a", "b", "c"], "b") |
| 1 |
| ``` |
| |
| In this example, the index of the first occurence of `"two"` is returned. |
| |
| ``` |
| > index(["one", "two", "two"], "two") |
| 1 |
| ``` |
| |
| ## Related Functions |
| |
| * [`element`](/terraform/language/functions/element) retrieves a particular element from a list given |
| its index. |
