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Last updated: Fri, 14 Nov 2008

explode

(PHP 4, PHP 5)

explode — Split a string by string

Description

array explode ( string $delimiter , string $string [, int $limit ] )

Returns an array of strings, each of which is a substring of string formed by splitting it on boundaries formed by the string delimiter .

Parameters

delimiter

The boundary string.

string

The input string.

limit

If limit is set, the returned array will contain a maximum of limit elements with the last element containing the rest of string .

If the limit parameter is negative, all components except the last -limit are returned.

Although implode() can, for historical reasons, accept its parameters in either order, explode() cannot. You must ensure that the delimiter argument comes before the string argument.

Return Values

If delimiter is an empty string (""), explode() will return FALSE. If delimiter contains a value that is not contained in string , then explode() will return an array containing string .

ChangeLog

Version	Description
5.1.0	Support for negative `limit` s was added
4.0.1	The `limit` parameter was added

Examples

Example #1 explode() examples


<?php
// Example 1
$pizza  = "piece1 piece2 piece3 piece4 piece5 piece6";
$pieces = explode(" ", $pizza);
echo $pieces[0]; // piece1
echo $pieces[1]; // piece2

// Example 2
$data = "foo:*:1023:1000::/home/foo:/bin/sh";
list($user, $pass, $uid, $gid, $gecos, $home, $shell) = explode(":", $data);
echo $user; // foo
echo $pass; // *

?>

Example #2 limit parameter examples


<?php
$str = 'one|two|three|four';

// positive limit
print_r(explode('|', $str, 2));

// negative limit (since PHP 5.1)
print_r(explode('|', $str, -1));
?>

The above example will output:

Array
(
    [0] => one
    [1] => two|three|four
)
Array
(
    [0] => one
    [1] => two
    [2] => three
)

Notes

Note: This function is binary-safe.


coroa at cosmo-genics dot com mentioned using preg_split() instead of explode() when you have multiple delimiters in your text and don't want your result array cluttered with empty elements. While that certainly works, it means you need to know your way around regular expressions... and, as it turns out, it is slower than its alternative. Specifically, you can cut execution time roughly in half if you use array_filter(explode(...)) instead.



Benchmarks (using 'too many spaces'):

Looped 100000 times:

preg_split: 1.61789011955 seconds

filter-explode: 0.916578054428 seconds



Looped 10000 times:

preg_split: 0.162719011307 seconds

filter-explode: 0.0918920040131 seconds



(The relation is, evidently, pretty linear.)



Note: Adding array_values() to the filter-explode combination, to avoid having those oft-feared 'holes' in your array, doesn't remove the benefit, either. (For scale - the '9' becomes a '11' in the benchmarks above.)



Also note: I haven't tested anything other than the example with spaces - since djogo_curl at yahoo's note seems to imply that explode() might get slow with longer delimiters, I expect this would be the case here, too.



I hope this helps someone. :)

seventoes at gmail dot com
10-Dec-2006 11:49


Note that explode, split, and functions like it, can accept more than a single character for the delimiter.



<?php

$string = "Something--next--something else--next--one more";



print_r(explode('--next--',$string));

?>

djogo_curl at yahoo
01-Dec-2004 08:50


Being a beginner in php but not so in Perl, I was used to split() instead of explode(). But as split() works with regexps it turned out to be much slower than explode(), when working with single characters.

coroa at cosmo-genics dot com
17-Nov-2003 12:01


To split a string containing multiple seperators between elements rather use preg_split than explode:



preg_split ("/\s+/", "Here  are    to    many  spaces in   between");



which gives you

array ("Here", "are", "to", "many", "spaces", "in", "between");

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