# substr_replace

(PHP 4, PHP 5)

substr_replace — Replace text within a portion of a string

### Description

mixed substr_replace ( mixed `$string` , string `$replacement` , int `$start` [, int `$length` ] )

substr_replace() replaces a copy of `string` delimited by the `start` and (optionally) `length` parameters with the string given in `replacement` .

### Parameters

`string`

  The input string.

`replacement`

  The replacement string.

`start`

  If `start` is positive, the replacing will begin at the `start` 'th offset into `string` .

  If `start` is negative, the replacing will begin at the `start` 'th character from the end of `string` .

`length`

  If given and is positive, it represents the length of the portion of `string` which is to be replaced. If it is negative, it represents the number of characters from the end of `string` at which to stop replacing. If it is not given, then it will default to strlen( `string` ); i.e. end the replacing at the end of `string` . Of course, if `length` is zero then this function will have the effect of inserting `replacement` into `string` at the given `start` offset.

### Return Values

The result string is returned. If `string` is an array then array is returned.

### Examples

Example#1 substr_replace() example

`<?php
$var = 'ABCDEFGH:/MNRPQR/';
echo "Original: $var<hr />\n";
/* These two examples replace all of $var with 'bob'. */
echo substr_replace($var, 'bob', 0) . "<br />\n";
echo substr_replace($var, 'bob', 0, strlen($var)) . "<br />\n";
/* Insert 'bob' right at the beginning of $var. */
echo substr_replace($var, 'bob', 0, 0) . "<br />\n";
/* These next two replace 'MNRPQR' in $var with 'bob'. */
echo substr_replace($var, 'bob', 10, -1) . "<br />\n";
echo substr_replace($var, 'bob', -7, -1) . "<br />\n";
/* Delete 'MNRPQR' from $var. */
echo substr_replace($var, '', 10, -1) . "<br />\n";
?>`

### Notes

> Note: This function is binary-safe.

### See Also

- str_replace()
- substr()