POSIX Regex

preg_replace

Last updated: Fri, 13 Nov 2009

preg_split

(PHP 4, PHP 5)

preg_split — Divide a string por uma expressão regular

Descrição

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

Divide uma dada string por uma expressão regular.

Parâmetros

pattern

O padrão a ser usado.

subject

A string de entrada.

limit

Se especificado, então somente limit pedaços da string serão retornados, e se limit for -1, significa "sem limite", que é útil quando especificando flags .

flags

flags pode ser uma combinação das seguintes flags (combinada com o operador | bit-a-bit):

PREG_SPLIT_NO_EMPTY: Se esta flag é usada, somente pedaços não vazios serão retornados pela preg_split().
PREG_SPLIT_DELIM_CAPTURE: Se esta flag é usada, expressão entre parênteses no padrão serão capturados e retornados também.
PREG_SPLIT_OFFSET_CAPTURE: Se esta flag é usada, para cada combinação o offset da string será também retornado. Note que isto modifica o valor de retorno em um array onde cada elemento é um array contendo a string combinada no índice 0 e o offset da mesma em subject no índice 1.

Valor Retornado

Retorna um array contendo pedaços de strings de subject divididos pelo que for combinado pelo pattern .

Histórico

Versão	Descrição
4.3.0	A `PREG_SPLIT_OFFSET_CAPTURE` foi adicionada
4.0.5	A `PREG_SPLIT_DELIM_CAPTURE` foi adicionada
4.0.0	O parâmetro `flags` foi adicionado

Exemplos

Exemplo #1 Exemplo da preg_split(): Obtendo partes de uma string


<?php
// reparte a frase por algum número caracteres de vírgula ou espaço,
// incluindo " ", \r, \t, \n e \f
$keywords = preg_split("/[\s,]+/", "hypertext language, programming");
?>

Exemplo #2 Dividindo a string em cada caractere que a compõe


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

Exemplo #3 Dividindo a string pela combinação e seus offsets


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

O exemplo acima irá imprimir:

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

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

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

)

Notas

Dica

Se você não precisa do poder das expressões regulares, pode optar por alternativa mais rápidas como explode() ou str_split().

Veja Também

spliti() - Separa strings em array utilizando expressões regulares insensíveis a maiúsculas e minúsculas
split() - Separa strings em array utilizando expressões regulares
implode() - Junta elementos de uma matriz em uma string
preg_match() - Perform a regular expression match
preg_match_all() - Perform a global regular expression match
preg_replace() - Perform a regular expression search and replace

POSIX Regex

preg_replace

Last updated: Fri, 13 Nov 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, 13 Nov 2009