Regex POSIX

preg_replace

Last updated: Fri, 10 Jul 2009

preg_split

(PHP 4, PHP 5)

preg_split — Éclate une chaîne par expression rationnelle

Description

array preg_split ( string $pattern , string $subject [, int $limit= -1 [, int $flags= 0 ]] )

Éclate une chaîne par expression rationnelle.

Liste de paramètres

pattern

Le masque à chercher, sous la forme d'une chaîne de caractères.

subject

La chaîne d'entrée.

limit

Si limit est spécifié, alors seules les limit premières sous-chaînes sont retournées et si limit vaut -1, cela signifie en fait "sans limite", ce qui est utile pour passer le paramètre flags .

flags

flags peut être la combinaison des options suivantes (combinées avec l'opérateur |):

PREG_SPLIT_NO_EMPTY: Si cette option est activée, seules les sous-chaînes non vides seront retournées par preg_split().
PREG_SPLIT_DELIM_CAPTURE: Si cette option est activée, les expressions entre parenthèses entre les délimiteurs de masques seront aussi capturées et retournées.
PREG_SPLIT_OFFSET_CAPTURE: Si cette option est activée, pour chaque résultat, la position de celui-ci sera retournée. Notez que cela change la valeur retournée en un tableau où chaque élément est un tableau constitué de la chaîne trouvée à la position 0 et la position de la chaîne dans subject à la position 1.

Valeurs de retour

Retourne un tableau contenant les sous-chaînes de subject , séparées par les chaînes qui vérifient pattern .

Historique

Version	Description
4.3.0	Le drapeau `PREG_SPLIT_OFFSET_CAPTURE` a été ajouté.
4.0.5	Le drapeau `PREG_SPLIT_DELIM_CAPTURE` a été ajouté.
4.0.0	Le paramètre `flags` a été ajouté.

Exemples

Exemple #1 Exemple avec preg_split() : Éclatement d'une chaîne de recherche


<?php
// scinde la phrase grâce aux virgules et espacements
// ce qui inclus les " ", \r, \t, \n et \f
$keywords = preg_split("/[\s,]+/", "langage hypertexte, programmation");
?>

Exemple #2 Scinder une chaîne en caractères


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

Exemple #3 Scinde une chaîne et capture les positions


<?php
$str = 'langage hypertexte, programmation';
$chars = preg_split('/ /', $str, -1, PREG_SPLIT_OFFSET_CAPTURE);
print_r($chars);
?>

L'exemple ci-dessus va afficher :

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

    [1] => Array
        (
            [0] => hypertexte,
            [1] => 8
        )

    [2] => Array
        (
            [0] => programmation
            [1] => 20
        )

)

Notes

Astuce

Si vous n'avez pas besoin de la puissance des expressions régulières, vous pouvez choisir des alternatives plus rapides (quoique plus simples) comme explode() ou str_split().

Voir aussi

spliti() - Scinde une chaîne en un tableau, grâce à une expression rationnelle
split() - Scinde une chaîne en un tableau, grâce à une expression rationnelle
implode() - Rassemble les éléments d'un tableau en une chaîne
preg_match() - Expression rationnelle standard
preg_match_all() - Expression rationnelle globale
preg_replace() - Rechercher et remplacer par expression rationnelle standard

Regex POSIX

preg_replace

Last updated: Fri, 10 Jul 2009

add a note User Contributed Notes
preg_split

wf
28-May-2009 04:36


Spacing out your CamelCase using preg_replace:



<?php



function spacify($camel, $glue = ' ') {

    return preg_replace( '/([a-z0-9])([A-Z])/', "$1$glue$2", $camel );

}



echo spacify('CamelCaseWords'), "\n"; // 'Camel Case Words'

echo spacify('camelCaseWords'), "\n"; // 'camel Case Words'



?>

chris AT cmbuckley DOT co DOT uk
27-May-2009 10:11


Here's a helpful function to space out your CamelCase using preg_split:





<?php





function spacify($camel, $glue = ' ') {


    return $camel[0] . substr(implode($glue, array_map('implode', array_chunk(preg_split('/([A-Z])/',


        ucfirst($camel), -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE), 2))), 1);


}





echo spacify('CamelCaseWords'); // 'Camel Case Words'


echo spacify('camelCaseWords'); // 'camel Case Words'





?>

kenorb at gmail dot com
23-May-2009 02:56


If you need convert function arguments without default default values and references, you can try this code:



<?php

    $func_args = '$node, $op, $a3 = NULL, $form = array(), $a4 = NULL'

    $call_arg = preg_match_all('@(?<func_arg>\$[^,= ]+)@i', $func_args, $matches);

    $call_arg = implode(',', $matches['func_arg']);

?>

Result: string = "$node,$op,$a3,$form,$a4"

bit_kahuna at yahoo dot com
27-Mar-2009 07:02


how to display a shortened text string with an elipsis, but on word boundaries only.





<?php


function truncate($string, $max = 70, $rep = '...') {





    $words = preg_split("/[\s]+/", $string);


    


    $newstring = '';


    $numwords = 0;


    


    foreach ($words as $word) {


        if ((strlen($newstring) + 1 + strlen($word)) < $max) {


            $newstring .= ' '.$word;


            ++$numwords;


        } else {


            break;


        }


    }





    if ($numwords < count($words)) {


        $newstring .= $rep;


    }


    


    return $newstring;


}


?>





hope this helps someone!  thanks for all the help from everyone else!!

csaba at alum dot mit dot edu
17-Mar-2009 09:06


If the task is too complicated for preg_split, preg_match_all might come in handy, since preg_split is essentially a special case.



I wanted to split a string on a certain character (asterisk), but only if it wasn't escaped (by a preceding backslash).  Thus, I should ensure an even number of backslashes before any asterisk meant as a splitter.  Look-behind in a regular expression wouldn't work since the length of the preceding backslash sequence can't be fixed.  So I turned to preg_match_all:



<?php

// split a string at unescaped asterisks

// where backslash is the escape character

$splitter = "/\\*((?:[^\\\\*]|\\\\.)*)/";

preg_match_all($splitter, "*$string", $aPieces, PREG_PATTERN_ORDER);

$aPieces = $aPieces[1];



// $aPieces now contains the exploded string

// and unescaping can be safely done on each piece

foreach ($aPieces as $idx=>$piece)

  $aPieces[$idx] = preg_replace("/\\\\(.)/s", "$1", $piece);

?>

anajilly
17-Jul-2008 08:17


<?php


$s = '<p>bleh blah</p><p style="one">one two three</p>';





$htmlbits = preg_split('/(<p( style="[-:a-z0-9 ]+")?>|<\/p>)/i', $s, -1, PREG_SPLIT_DELIM_CAPTURE);





print_r($htmlbits);


?>





Array


(


    [0] =>


    [1] => <p>


    [2] => bleh blah


    [3] => </p>


    [4] =>


    [5] => <p style="one">


    [6] =>  style="one"


    [7] => one two three


    [8] => </p>


    [9] =>


)





two interesting bits:





1. When using PREG_SPLIT_DELIM_CAPTURE, if you use more than one pair of parentheses, the result array can have members representing all pairs.  See array indexes 5 and 6 to see two adjacent delimiter results in which the second is a subset match of the first.





2. If a parenthesised sub-expression is made optional by a following question mark (ex: '/abc (optional subregex)?/') some split delimiters may be captured in the result while others are not.  See array indexes 1 and 2 to see an instance where the overall match succeeded and returned a delimiter while the optional sub-expression '( style="[-:a-z0-9 ]+")?' did not match, and did not return a delimiter.  This means it's possible to have a result with an unpredictable number of delimiters in the result array.





This second aspect is true irrespective of the number of pairs of parentheses in the regex.  This means: in a regular expression with a single optional parenthesised sub-expression, the overall expression can match without generating a corresponding delimiter in the result.

m dot timmermans at home dot NOSPAM dot nl
29-May-2008 10:56


For people who want to use the double quote to group words/fields, kind of like CSV does, you can use the following expression:

<?php

$keywords = preg_split( "/[\s,]*\\\"([^\\\"]+)\\\"[\s,]*|[\s,]+/", "textline with, commas and \"quoted text\" inserted", 0, PREG_SPLIT_DELIM_CAPTURE );

?>

Which will result in:

Array

(

    [0] => textline

    [1] => with

    [2] => commas

    [3] => and

    [4] => quoted text

    [5] => inserted

)

crispytwo at yahoo dot com
04-Sep-2007 08:29


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.

Steve
23-Mar-2005 04:41


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:





<?php 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 03:01


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





<?php


$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 07:01


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.

add a note

Regex POSIX

preg_replace

Last updated: Fri, 10 Jul 2009