# index_of()

Returns the location (index) of the specified characters.

## Syntax

`index_of`(*string*, *searchStr* \[,*position* \[, *occurence*]])

## Usage

This function returns the index of *searchStr* in *string*, beginning at the specified *position*. The function returns 0 if *searchStr* is not found. This function is case-sensitive. If any of the parameters are *null*, then the function returns *null*.

The default value of *position* is 1, which means that the function begins searching at the first character of *string*. An error results if *position* is negative or zero.

*occurrence* is an optional integer, with a default value of `1` . You can use this parameter to specify which occurrence of *searchStr* to search for. For example, if there is more than one occurrence of *searchStr*, and *occurence* is 2, the index of the second occurrence is returned.

Constant values are supported for *position* and *occurrence*, not arbitrary expressions.

If *searchStr* is an empty string, then the function returns *null*.

## Example

```nolang
q = load "Opportunity Details";
q = group q by all;
-- return the first occurrence of "a", starting at the beginning.
-- The result is 2.
q = foreach q generate index_of("Hawaii", "a") as 'Index';

-- return the second occurrence of "a", starting at the beginning
-- the result is 4
q = foreach q generate index_of("Hawaii", "a",1, 2) as 'Index';


-- return the first occurrence of "a", starting at the third position
-- the result is 4
q = foreach q generate index_of("Hawaii", "a",3) as 'Index';
```