preg_split

(PHP 4, PHP 5, PHP 7, PHP 8)

preg_split — Split string by a regular expression

Description

preg_split(
    string $pattern,
    string $subject,
    int $limit = -1,
    int $flags = 0
): array|false

Split the given string by a regular expression.

Parameters

pattern

The pattern to search for, as a string.

subject

The input string.

limit

If specified, then only substrings up to limit are returned with the rest of the string being placed in the last substring. A limit of -1 or 0 means "no limit".

flags

flags can be any combination of the following flags (combined with the | bitwise operator):

PREG_SPLIT_NO_EMPTY
If this flag is set, only non-empty pieces will be returned by preg_split().
PREG_SPLIT_DELIM_CAPTURE
If this flag is set, parenthesized expression in the delimiter pattern will be captured and returned as well.
PREG_SPLIT_OFFSET_CAPTURE

If this flag is set, for every occurring match the appendant string offset will also be returned. Note that this changes the return value in an array where every element is an array consisting of the matched string at offset 0 and its string offset into subject at offset 1.

Return Values

Returns an array containing substrings of subject split along boundaries matched by pattern, or false on failure.

Errors/Exceptions

If the regex pattern passed does not compile to a valid regex, an E_WARNING is emitted.

Examples

Example #1 preg_split() example : Get the parts of a search string

<?php
// split the phrase by any number of commas or space characters,
// which include " ", \r, \t, \n and \f
$keywords = preg_split("/[\s,]+/", "hypertext language, programming");
print_r($keywords);
?>

The above example will output:

Array
(
    [0] => hypertext
    [1] => language
    [2] => programming
)

Example #2 Splitting a string into component characters

<?php
$str = 'string';
$chars = preg_split('//', $str, -1, PREG_SPLIT_NO_EMPTY);
print_r($chars);
?>

The above example will output:

Array
(
    [0] => s
    [1] => t
    [2] => r
    [3] => i
    [4] => n
    [5] => g
)

Example #3 Splitting a string into matches and their offsets

<?php
$str = 'hypertext language programming';
$chars = preg_split('/ /', $str, -1, PREG_SPLIT_OFFSET_CAPTURE);
print_r($chars);
?>

The above example will output:

Array
(
    [0] => Array
        (
            [0] => hypertext
            [1] => 0
        )

    [1] => Array
        (
            [0] => language
            [1] => 10
        )

    [2] => Array
        (
            [0] => programming
            [1] => 19
        )

)

Notes

Tip

If you don't need the power of regular expressions, you can choose faster (albeit simpler) alternatives like explode() or str_split().

Tip

If matching fails, an array with a single element containing the input string will be returned.

See Also