The preg_grep Function

The preg_grep function returns an array of elements that match a given regular expression. The first parameter of the function accepts a string with a regular expression, and the second - the array to search. The third optional parameter determines whether to return elements that do not match the regular expression.

Syntax

preg_grep(pattern, array, [flags]);

Flags

Flag	Description
`PREG_GREP_INVERT`	Inverts the result - returns elements that do NOT match the pattern.
`PREG_GREP_NO_ERROR`	Does not generate an error for invalid regular expression (PHP 8.1+).

Example

Let's find all array elements that start with a digit:

<?php
	$arr = ['a1', '2b', 'c3', '4d', 'e5'];
	$res = preg_grep('/^\d/', $arr);
	var_dump($res);
?>

Code execution result:

['2b', '4d']

Example

Use the PREG_GREP_INVERT flag to get elements that do NOT match the regular expression:

<?php
	$arr = ['a1', '2b', 'c3', '4d', 'e5'];
	$res = preg_grep('/^\d/', $arr, PREG_GREP_INVERT);
	var_dump($res);
?>

Code execution result:

['a1', 'c3', 'e5']

Example

Find all array elements containing only digits:

<?php
	$arr = ['123', 'abc', '45', 'de', '678'];
	$res = preg_grep('/^\d+$/', $arr);
	var_dump($res);
?>

Code execution result:

['123', '45', '678']

The preg_grep Function

Syntax

Flags

Example

Example

Example

See Also