POSIX Regex

preg_replace

Last updated: Fri, 30 Oct 2009

preg_split

(PHP 4, PHP 5)

preg_split — Zerlegt eine Zeichenkette anhand eines regulären Ausdrucks

Beschreibung

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

Zerlegt die angegebene Zeichenkette anhand eines regulären Ausdrucks.

Parameter-Liste

pattern

Der Ausdruck, nach dem gesucht werden soll, als Zeichenkette.

subject

Die zu zerlegende Zeichenkette.

limit

Falls angegeben, werden maximal limit Teilzeichenketten zurückgegeben und falls limit -1 ist, bedeutet das "kein Limit", was für die Angabe von flags sinnvoll ist.

flags

flags kann jede Kombination der folgenden Flags sein (verknüpft mit dem bitweisen | Operator):

PREG_SPLIT_NO_EMPTY: Falls dieses Flag gesetzt ist, werden von preg_split() nur die Teile zurückgegeben, die nicht leer sind.
PREG_SPLIT_DELIM_CAPTURE: Falls dieses Flag gesetzt ist, werden auch die eingeklammerten Ausdrücke des Trennsymbol-Suchmusters erfasst und zurückgegeben.
PREG_SPLIT_OFFSET_CAPTURE: Falls dieses Flag gesetzt ist, wird mit jeder gefundenen Übereinstimmung der dazugehörige Versatz in der Zeichenkette zurückgegeben. Beachten Sie, dass dies die Rückgabewerte in einem Array dahingehend ändert, dass jedes Element ein Array ist, das aus der übereinstimmenden Zeichenkette als Element 0 und deren Stelle in subject als Element 1 besteht.

Rückgabewerte

Gibt ein Array zurück, bestehend aus Teilzeichenketten der subject , die an den auf das pattern passenden Stellen zerlegt wurde.

Changelog

Version	Beschreibung
4.3.0	Das Flag `PREG_SPLIT_OFFSET_CAPTURE` hinzugefügt
4.0.5	Das Flag `PREG_SPLIT_DELIM_CAPTURE` hinzugefügt
4.0.0	Den Parameter `flags` hinzugefügt

Beispiele

Beispiel #1 preg_split() Beispiel: Eine Zeichenkette in ihre Bestandteile zerlegen


<?php
// zerlegt die Zeichenkette an Stellen mit beliebiger Anzahl von
// Kommata oder Leerzeichen, die " ", \r, \t, \n und \f umfassen
$schluesselwoerter = preg_split("/[\s,]+/", "hypertext language, programming");
?>

Beispiel #2 Eine Zeichenkette in einzelne Zeichen zerlegen


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

Beispiel #3 Eine Zeichenkette in Übereinstimmungen mit dem Suchmuster und deren Versatz zerlegen


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

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

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

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

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

)

Anmerkungen

Tipp

Falls Sie die Leistung regulärer Ausdrücke nicht benötigen, können Sie stattdessen schnellere (wenngleich einfachere) Alternativen wie explode() oder str_split() verwenden.

Siehe auch

spliti() - Zerlegt eine Zeichenkette anhand eines regulären Ausdrucks ohne Berücksichtigung von Groß-/Kleinschreibung in ein Array
split() - Zerlegt eine Zeichenkette anhand eines regulären Ausdrucks in ein Array
implode() - Verbindet Array-Elemente zu einem String
preg_match() - Führt eine Suche mit einem regulären Ausdruck durch
preg_match_all() - Führt eine umfassende Suche nach Übereinstimmungen mit regulärem Ausdruck durch
preg_replace() - Sucht und ersetzt einen regulären Ausdruck

POSIX Regex

preg_replace

Last updated: Fri, 30 Oct 2009

add a note User Contributed Notes
preg_split

jan dot sochor at icebolt dot info
24-Oct-2009 10:26


Sometimes PREG_SPLIT_DELIM_CAPTURE does strange results.



<?php

$content = '<strong>Lorem ipsum dolor</strong> sit <img src="test.png" />amet <span class="test" style="color:red">consec<i>tet</i>uer</span>.';

$chars = preg_split('/<[^>]*[^\/]>/i', $content, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);

print_r($chars);

?>

Produces:

Array

(

    [0] => Lorem ipsum dolor

    [1] =>  sit <img src="test.png" />amet 

    [2] => consec

    [3] => tet

    [4] => uer

)



So that the delimiter patterns are missing. If you wanna get these patters remember to use parentheses.



<?php

$chars = preg_split('/(<[^>]*[^\/]>)/i', $content, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);

print_r($chars); //parentheses added

?>

Produces:

Array

(

    [0] => <strong>

    [1] => Lorem ipsum dolor

    [2] => </strong>

    [3] =>  sit <img src="test.png" />amet 

    [4] => <span class="test" style="color:red">

    [5] => consec

    [6] => <i>

    [7] => tet

    [8] => </i>

    [9] => uer

    [10] => </span>

    [11] => .

)

php at dmi dot me dot uk
06-Oct-2009 08:23


To split a camel-cased string using preg_split() with lookaheads and lookbehinds:



<?php

function splitCamelCase($str) {

  return preg_split('/(?<=\\w)(?=[A-Z])/', $str);

}

?>

Peter -the pete- de Pijd
24-Sep-2009 09:34


If you want to use something like explode(PHP_EOL, $string) but for all combinations of \r and \n, try this one:





<?php


$text = "A\nB\rC\r\nD\r\rE\n\nF";


$texts = preg_split("/((\r(?!\n))|((?<!\r)\n)|(\r\n))/", $text);


?>





result:


array("A", "B", "C", "D", "", "E", "", "F");

buzoganylaszlo at yahoo dot com
01-Aug-2009 07:57


Extending m.timmermans's solution, you can use the following code as a search expression parser:



<?php

$search_expression = "apple bear \"Tom Cruise\" or 'Mickey Mouse' another word";

$words = preg_split("/[\s,]*\\\"([^\\\"]+)\\\"[\s,]*|" . "[\s,]*'([^']+)'[\s,]*|" . "[\s,]+/", $search_expression, 0, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);

print_r($words);

?>



The result will be:

Array

(

    [0] => apple

    [1] => bear

    [2] => Tom Cruise

    [3] => or

    [4] => Mickey Mouse

    [5] => another

    [6] => word

)



1. Accepted delimiters: white spaces (space, tab, new line etc.) and commas.



2. You can use either simple (') or double (") quotes for expressions which contains more than one word.

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

POSIX Regex

preg_replace

Last updated: Fri, 30 Oct 2009