preg_replace
PREG_SPLIT_OFFSET_CAPTURE should be maintained for UTF-8 characters, because it produces wrong results as if it is using strlen() internally, instead of using mb_strlen(), which is the right one...
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
add a note
User Contributed Notes
preg_split
w o z 2 2 a t y a h o o d o t c o m
23-Aug-2011 12:42
david dot binovec at gmail dot com
26-Jun-2011 03:38
Limit = 1 may be confusing. The important thing is that in case of limit equals to 1 will produce only ONE substring. Ergo the only one substring will be the first one as well as the last one. Tnat the rest of the string (after the first delimiter) will be placed to the last substring. But last is the first and only one.
<?php
$output = $preg_split('(/ /)', '1 2 3 4 5 6 7 8', 1);
echo $output[0] //will return whole string!;
$output = $preg_split('(/ /)', '1 2 3 4 5 6 7 8', 2);
echo $output[0] //will return 1;
echo $output[1] //will return '2 3 4 5 6 7 8';
?>
eric at clarinova dot com
25-Jun-2011 12:04
Here is another way to split a CamelCase string, which is a simpler expression than the one using lookaheads and lookbehinds:
preg_split('/([[:upper:]][[:lower:]]+)/', $last, null, PREG_SPLIT_DELIM_CAPTURE|PREG_SPLIT_NO_EMPTY)
It makes the entire CamelCased word the delimiter, then returns the delimiters (PREG_SPLIT_DELIM_CAPTURE) and omits the empty values between the delimiters (PREG_SPLIT_NO_EMPTY)
PhoneixSegovia at gmail dot com
26-Nov-2010 01:38
You must be caution when using lookbehind to a variable match.
For example:
'/(?<!\\\)\r?\n)/'
to match a new line when not \ is before it don't go as spected as it match \r as the lookbehind (becouse isn't a \) and is optional before \n.
You must use this for example:
'/((?<!\\\|\r)\n)|((?<!\\\)\r\n)/'
That match a alone \n (not preceded by \r or \) or a \r\n not preceded by a \.
Daniel Schroeder
03-Nov-2010 12:46
If you want to split by a char, but want to ignore that char in case it is escaped, use a lookbehind assertion.
In this example a string will be split by ":" but "\:" will be ignored:
<?php
$string='a:b:c\:d';
$array=preg_split('#(?<!\\\)\:#',$string);
print_r($array);
?>
Results into:
Array
(
[0] => a
[1] => b
[2] => c\:d
)
sergei dot garrison at gmail dot com
05-Mar-2010 05:04
If you need to split a list of "tags" while allowing for user error, you'll find this more useful than the manual's first example.
<?php
$string = 'one, two,three, four , five,six seven';
$array = preg_split("/[\s]*[,][\s]*/", $string);
print_r($array);
// Array ( [0] => one [1] => two [2] => three [3] => four [4] => five [5] => six seven )
?>
This splits the string *only* by commas, regardless of how many spaces there are on either side of any comma.
nesbert at gmail dot com
29-Jan-2010 12:46
Hope this helps someone...
<?php
/**
* Split a string into groups of words with a line no longer than $max
* characters.
*
* @param string $string
* @param integer $max
* @return array
**/
function split_words($string, $max = 1)
{
$words = preg_split('/\s/', $string);
$lines = array();
$line = '';
foreach ($words as $k => $word) {
$length = strlen($line . ' ' . $word);
if ($length <= $max) {
$line .= ' ' . $word;
} else if ($length > $max) {
if (!empty($line)) $lines[] = trim($line);
$line = $word;
} else {
$lines[] = trim($line) . ' ' . $word;
$line = '';
}
}
$lines[] = ($line = trim($line)) ? $line : $word;
return $lines;
}
?>
jan dot sochor at icebolt dot info
24-Oct-2009 12:26
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 10:23
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 11:34
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 09:57
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 06:36
Spacing out your CamelCase using preg_replace:
<?php
function spacify($camel, $glue = ' ') {
return preg_replace( '/([a-z0-9])([A-Z])/', "$1$glue$2", $camel );
}
echo spacify('CamelCaseWords'), "\n"; // 'Camel Case Words'
echo spacify('camelCaseWords'), "\n"; // 'camel Case Words'
?>
chris AT cmbuckley DOT co DOT uk
27-May-2009 12:11
Here's a helpful function to space out your CamelCase using preg_split:
<?php
function spacify($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 04:56
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 08:02
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 10:06
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 10:17
<?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 12:56
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 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.
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:
<?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 05:01
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 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.