POSIX Regex

preg_replace

Last updated: Fri, 03 Jul 2009

preg_split

(PHP 4, PHP 5)

preg_split — 정규 표현식에 따라 문자열을 나눔

설명

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

정규 표현식에 따라서 주어진 문자열을 나눕니다.

인수

pattern

검색할 패턴 문자열.

subject

입력 문자열.

limit

지정하면, limit 회까지 나눠진 문자열을 반환하며, limit 가 -1이면 "무제한"을 의미합니다. 이 값은 flags 를 지정할 때 유용합니다.

flags

flags 는 다음 플래그들을 조합할 수 있습니다 (bitwise | 연산자로 조합합니다) :

PREG_SPLIT_NO_EMPTY: 이 플래그를 설정하면, preg_split()에 의해 나눈 후 비어있지 않은 조각만을 반환합니다.
PREG_SPLIT_DELIM_CAPTURE: 이 플래그를 설정하면, 구분자 패턴 안의 서브패턴도 검출하여 반환합니다.
PREG_SPLIT_OFFSET_CAPTURE: 이 플래그를 설정하면, 문자열의 시작 위치도 반환합니다. 반환값이 매치된 문자열을 오프셋 0으로, 문자열 시작 위치를 오프셋 1로 가지는 배열을 원소로 갖는 배열로 변하는 점에 주의하십시오.

반환값

pattern 에 매치한 경계로 나눠진 subject 의 부분을 가진 배열을 반환합니다.

변경점

버전	설명
4.3.0	`PREG_SPLIT_OFFSET_CAPTURE` 추가
4.0.5	`PREG_SPLIT_DELIM_CAPTURE` 추가
4.0.0	`flags` 인수 추가

예제

Example #1 preg_split() 예제 : 검색 문자열의 일부만을 얻기


<?php
// " ", \r, \t, \n, \f를 포함하여
// 임의 갯수의 콤마와 스페이스로 구문을 나눕니다.
$keywords = preg_split("/[\s,]+/", "hypertext language, programming");
?>

Example #2 문자열을 구성 문자로 나누기.


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

Example #3 매치와 시작위치로 문자열을 나누기.


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

위 예제의 출력:

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

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

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

)

주의

Tip

정규 표현식의 힘이 필요하지 않으면, 더 빠른(그리고 간단한) explode()나 str_split()로 대체할 수 있습니다.

참고

spliti() - Split string into array by regular expression case insensitive
split() - Split string into array by regular expression
implode() - 문자열로 배열 원소를 결합
preg_match() - 정규표현식 매치를 수행
preg_match_all() - 전역 정규 표현식 매치를 수행합니다
preg_replace() - 정규 표현식 검색과 치환을 수행

POSIX Regex

preg_replace

Last updated: Fri, 03 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

POSIX Regex

preg_replace

Last updated: Fri, 03 Jul 2009