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PCRE Funkcje

Last updated: Fri, 11 Apr 2008

preg_split

(PHP 4, PHP 5)

preg_split — Split string by a regular expression

Opis

array preg_split ( string $pattern , string $subject [, int $limit [, int $flags ]] )

Split the given string by a regular expression.

Parametry

pattern

The pattern to search for, as a string.

subject

The input string.

limit

If specified, then only substrings up to limit are returned, and if limit is -1, it actually means "no limit", which is useful for specifying the flags .

flags

flags can be any combination of the following flags (combined with 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.

Zwracane wartości

Returns an array containing substrings of subject split along boundaries matched by pattern .

Rejestr zmian

Wersja	Opis
4.3.0	The `PREG_SPLIT_OFFSET_CAPTURE` was added
4.0.5	The `PREG_SPLIT_DELIM_CAPTURE` was added
4.0.0	The `flags` parameter was added

Przykłady

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");
?>

Example #2 Splitting a string into component characters


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

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);
?>

Powyższy przykład wyświetli:

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

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

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

)

Notatki

Wskazówka

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

Patrz także

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PCRE Funkcje

Last updated: Fri, 11 Apr 2008

add a note User Contributed Notes
preg_split

crispytwo at yahoo dot com
04-Sep-2007 10:29


I was having trouble getting the PREG_SPLIT_DELIM_CAPTURE flag to work because I missed reading the "parenthesized expression" in the documentation :-(  



So the pattern should look like:

/(A)/

not just 

/A/

and it works as described/expected.

me
14-Nov-2006 02:56


[Editor's Note: You can use php's wordwrap() to do the exact same thing]





This script splits a text into portions of a defined max. size, which will never be exceeded, and doesnt cut words. (Per portion it adds as many words as possible without exceeding the char-limit)





the only exception where a portion would be bigger than the limit, is when there's a word thats longer than the max_size, but you could quite easily change the script so it regards this.





<?


$str= 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.';





$max_size = 50;


$words = preg_split("/[\040]+/", $str, -1);





$r=0;


for($i=0; $i < count($words); $i++) {


if (strlen($line[$r] . $words[$i] . ' ') < $max_size) $line[$r] .= $words[$i] . ' ';


else


    {


        $r++;


        $line[$r] .= $words[$i] . ' ';


    }


}


print_r ($line);


?>





Result:





Array


(


    [0] => Lorem ipsum dolor sit amet, consectetur 


    [1] => adipisicing elit, sed do eiusmod tempor 


    [2] => incididunt ut labore et dolore magna aliqua. Ut 


    [3] => enim ad minim veniam, quis nostrud exercitation 


    [4] => ullamco laboris nisi ut aliquip ex ea commodo 


    [5] => consequat. Duis aute irure dolor in 


    [6] => reprehenderit in voluptate velit esse cillum 


    [7] => dolore eu fugiat nulla pariatur. Excepteur sint 


    [8] => occaecat cupidatat non proident, sunt in culpa 


    [9] => qui officia deserunt mollit anim id est laborum. 


)

superzouz at hotmail dot com
04-Dec-2005 02:53


Be advised



$arr = preg_split("/x/", "x" );

print_r($arr);



will output:



Array

(

    [0] => 

    [1] => 

)



That is it will catch the 2 empty string on each side of the delimiter.

Steve
23-Mar-2005 05:41


preg_split() behaves differently from perl's split() if the string ends with a delimiter. This perl snippet will print 5:



my @a = split(/ /, "a b c d e ");

print scalar @a;



The corresponding php code prints 6:



print count(preg_split("/ /", "a b c d e "));



This is not necessarily a bug (nowhere does the documentation say that preg_split() behaves the same as perl's split()) but it might surprise perl programmers.

jetsoft at iinet.net.au
25-Sep-2004 05:01


To clarify the "limit" parameter and the PREG_SPLIT_DELIM_CAPTURE option,



$preg_split('(/ /)', '1 2 3 4 5 6 7 8', 4 ,PREG_SPLIT_DELIM_CAPTURE );

returns



('1', ' ', '2', ' ' , '3', ' ', '4 5 6 7 8')



So you actually get 7 array items not 4

dave at codewhore dot org
29-May-2002 09:01


The above description for PREG_SPLIT_OFFSET_CAPTURE may be a bit confusing.



When the flag is or'd into the 'flags' parameter of preg_split, each match is returned in the form of a two-element array. For each of the two-element arrays, the first element is the matched string, while the second is the match's zero-based offset in the input string.



For example, if you called preg_split like this:



preg_split('/foo/', 'matchfoomatch', -1, PREG_SPLIT_OFFSET_CAPTURE);



it would return an array of the form:



Array(

  [0] => Array([0] => "match", [1] => 0),

  [1] => Array([1] => "match", [1] => 8)

)



Note that or'ing in PREG_DELIM_CAPTURE along with PREG_SPLIT_OFFSET_CAPTURE works as well.

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PCRE Funkcje

Last updated: Fri, 11 Apr 2008