---
title: regexp.findStringIndex() function
description: >
  `regexp.findStringIndex()` returns a two-element array of integers that represent the
  beginning and ending indexes of the first regular expression match in a string.
menu:
  flux_v0_ref:
    name: regexp.findStringIndex
    parent: regexp
    identifier: regexp/findStringIndex
weight: 101
---

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`regexp.findStringIndex()` returns a two-element array of integers that represent the
beginning and ending indexes of the first regular expression match in a string.



##### Function type signature

```js
(r: regexp, v: string) => [int]
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### r
({{< req >}})
Regular expression used to search `v`.



### v
({{< req >}})
String value to search.




## Examples

### Index the bounds of first regular expression match in each row

```js
import "regexp"

regexp.findStringIndex(r: /ab?/, v: "tablet")// Returns [1, 3]


```