preg_match_all

(PHP 4, PHP 5, PHP 7)

preg_match_all — Perform a global regular expression match

Description

int preg_match_all ( string $pattern , string $subject [, array &$matches [, int $flags = PREG_PATTERN_ORDER [, int $offset = 0 ]]] )

Searches subject for all matches to the regular expression given in pattern and puts them in matches in the order specified by flags.

After the first match is found, the subsequent searches are continued on from end of the last match.

Parameters

pattern

The pattern to search for, as a string.

subject

The input string.

matches

Array of all matches in multi-dimensional array ordered according to flags.

flags

Can be a combination of the following flags (note that it doesn't make sense to use PREG_PATTERN_ORDER together with PREG_SET_ORDER):

PREG_PATTERN_ORDER

Orders results so that $matches[0] is an array of full pattern matches, $matches[1] is an array of strings matched by the first parenthesized subpattern, and so on.


<?php
preg_match_all("|<[^>]+>(.*)</[^>]+>|U",
    "<b>example: </b><div align=left>this is a test</div>",
    $out, PREG_PATTERN_ORDER);
echo $out[0][0] . ", " . $out[0][1] . "\n";
echo $out[1][0] . ", " . $out[1][1] . "\n";
?>

The above example will output:

<b>example: </b>, <div align=left>this is a test</div>
example: , this is a test

So, $out[0] contains array of strings that matched full pattern, and $out[1] contains array of strings enclosed by tags.

PREG_SET_ORDER

Orders results so that $matches[0] is an array of first set of matches, $matches[1] is an array of second set of matches, and so on.


<?php
preg_match_all("|<[^>]+>(.*)</[^>]+>|U",
    "<b>example: </b><div align=\"left\">this is a test</div>",
    $out, PREG_SET_ORDER);
echo $out[0][0] . ", " . $out[0][1] . "\n";
echo $out[1][0] . ", " . $out[1][1] . "\n";
?>

The above example will output:

<b>example: </b>, example:
<div align="left">this is a test</div>, this is a test

PREG_OFFSET_CAPTURE

If this flag is passed, for every occurring match the appendant string offset will also be returned. Note that this changes the value of matches into an array where every element is an array consisting of the matched string at offset 0 and its string offset into subject at offset 1.

If no order flag is given, PREG_PATTERN_ORDER is assumed.

offset

Normally, the search starts from the beginning of the subject string. The optional parameter offset can be used to specify the alternate place from which to start the search (in bytes).

Note:
Using offset is not equivalent to passing substr($subject, $offset) to preg_match_all() in place of the subject string, because pattern can contain assertions such as ^, $ or (?<=x). See preg_match() for examples.

Return Values

Returns the number of full pattern matches (which might be zero), or FALSE if an error occurred.

Changelog

Version	Description
5.4.0	The `matches` parameter became optional.
5.3.6	Returns `FALSE` if `offset` is higher than `subject` length.
5.2.2	Named subpatterns now accept the syntax (?<name>) and (?'name') as well as (?P<name>). Previous versions accepted only (?P<name>).

Examples

Example #1 Getting all phone numbers out of some text.


<?php
preg_match_all("/\(?  (\d{3})?  \)?  (?(1)  [\-\s] ) \d{3}-\d{4}/x",
                "Call 555-1212 or 1-800-555-1212", $phones);
?>

Example #2 Find matching HTML tags (greedy)


<?php
// The \\2 is an example of backreferencing. This tells pcre that
// it must match the second set of parentheses in the regular expression
// itself, which would be the ([\w]+) in this case. The extra backslash is
// required because the string is in double quotes.
$html = "<b>bold text</b><a href=howdy.html>click me</a>";

preg_match_all("/(<([\w]+)[^>]*>)(.*?)(<\/\\2>)/", $html, $matches, PREG_SET_ORDER);

foreach ($matches as $val) {
    echo "matched: " . $val[0] . "\n";
    echo "part 1: " . $val[1] . "\n";
    echo "part 2: " . $val[2] . "\n";
    echo "part 3: " . $val[3] . "\n";
    echo "part 4: " . $val[4] . "\n\n";
}
?>

The above example will output:

matched: <b>bold text</b>
part 1: <b>
part 2: b
part 3: bold text
part 4: </b>

matched: <a href=howdy.html>click me</a>
part 1: <a href=howdy.html>
part 2: a
part 3: click me
part 4: </a>

Example #3 Using named subpattern


<?php

$str = <<<FOO
a: 1
b: 2
c: 3
FOO;

preg_match_all('/(?P<name>\w+): (?P<digit>\d+)/', $str, $matches);

/* This also works in PHP 5.2.2 (PCRE 7.0) and later, however 
 * the above form is recommended for backwards compatibility */
// preg_match_all('/(?<name>\w+): (?<digit>\d+)/', $str, $matches);

print_r($matches);

?>

The above example will output:

Array
(
    [0] => Array
        (
            [0] => a: 1
            [1] => b: 2
            [2] => c: 3
        )

    [name] => Array
        (
            [0] => a
            [1] => b
            [2] => c
        )

    [1] => Array
        (
            [0] => a
            [1] => b
            [2] => c
        )

    [digit] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

    [2] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

)

User Contributed Notes

john at mccarthy dot net

5 years ago


I needed a function to rotate the results of a preg_match_all query, and made this. Not sure if it exists.



<?php

function turn_array($m)

{

    for ($z = 0;$z < count($m);$z++)

    {

        for ($x = 0;$x < count($m[$z]);$x++)

        {

            $rt[$x][$z] = $m[$z][$x];

        }

    }    

    

    return $rt;

}

?>



Example - Take results of some preg_match_all query:



Array

(

    [0] => Array

        (

            [1] => Banff 

            [2] => Canmore

            [3] => Invermere

        )

 

    [1] => Array

        (

            [1] => AB 

            [2] => AB

            [3] => BC

        )

 

    [2] => Array

        (

            [1] => 51.1746254 

            [2] => 51.0938416

            [3] => 50.5065193

        )

 

    [3] => Array

        (

            [1] => -115.5719757 

            [2] => -115.3517761

            [3] => -116.0321884

        )

 

    [4] => Array

        (

            [1] => T1L 1B3 

            [2] => T1W 1N2

            [3] => V0B 2G0

        )



)



Rotate it 90 degrees to group results as records:



Array

(

    [0] => Array

        (

            [1] => Banff 

            [2] => AB

            [3] => 51.1746254

            [4] => -115.5719757

            [5] => T1L 1B3

        )

 

    [1] => Array

        (

            [1] => Canmore

            [2] => AB

            [3] => 51.0938416

            [4] => -115.3517761

            [5] => T1W 1N2

        )

 

    [2] => Array

        (

            [1] => Invermere

            [2] => BC

            [3] => 50.5065193

            [4] => -116.0321884

            [5] => V0B 2G0

        )

)

Daniel Klein

11 months ago


The code that john at mccarthy dot net posted is not necessary. If you want your results grouped by individual match simply use:

<?
preg_match_all($pattern, $string, $matches, PREG_SET_ORDER);
?>

E.g.

<?
preg_match_all('/([GH])([12])([!?])/', 'G1? H2!', $matches); // Default PREG_PATTERN_ORDER
// $matches = array(0 => array(0 => 'G1?', 1 => 'H2!'),
//                  1 => array(0 => 'G', 1 => 'H'),
//                  2 => array(0 => '1', 1 => '2'),
//                  3 => array(0 => '?', 1 => '!'))

preg_match_all('/([GH])([12])([!?])/', 'G1? H2!', $matches, PREG_SET_ORDER);
// $matches = array(0 => array(0 => 'G1?', 1 => 'G', 2 => '1', 3 => '?'),
//                  1 => array(0 => 'H2!', 1 => 'H', 2 => '2', 3 => '!'))
?>

fab

3 years ago


Here is a function that replaces all occurrences of a number in a string by the number--

<?php
function decremente_chaine($chaine)
    {
        //récupérer toutes les occurrences de nombres et leurs indices
        preg_match_all("/[0-9]+/",$chaine,$out,PREG_OFFSET_CAPTURE);
            //parcourir les occurrences 
            for($i=0;$i<sizeof($out[0]);$i++)
            {
                $longueurnombre = strlen((string)$out[0][$i][0]);
                $taillechaine = strlen($chaine);
                // découper la chaine en 3 morceaux
                $debut = substr($chaine,0,$out[0][$i][1]);
                $milieu = ($out[0][$i][0])-1;
                $fin = substr($chaine,$out[0][$i][1]+$longueurnombre,$taillechaine);
                 // si c'est 10,100,1000 etc. on décale tout de 1 car le résultat comporte un chiffre de moins
                 if(preg_match('#[1][0]+$#', $out[0][$i][0]))
                 {
                    for($j = $i+1;$j<sizeof($out[0]);$j++)
                    {
                        $out[0][$j][1] = $out[0][$j][1] -1;
                    }
                 }
                $chaine = $debut.$milieu.$fin;
            }
        return $chaine;
    }
?>

meaneye at mail dot com

7 years ago


Recently I had to write search engine in hebrew and ran into huge amount of problems. My data was stored in MySQL table with utf8_bin encoding.

So, to be able to write hebrew in utf8 table you need to do
<?php
$prepared_text = addslashes(urf8_encode($text));
?>

But then I had to find if some word exists in stored text. This is the place I got stuck. Simple preg_match would not find text since hebrew doesnt work that easy. I've tried with /u and who kows what else.

Solution was somewhat logical and simple... 
<?php
$db_text = bin2hex(stripslashes(utf8_decode($db_text)));
$word = bin2hex($word);

$found = preg_match_all("/($word)+/i", $db_text, $matches);
?>

I've used preg_match_all since it returns number of occurences. So I could sort search results acording to that.

Hope someone finds this useful!

buuh

5 years ago


if you want to extract all {token}s from a string:

<?php
$pattern = "/{[^}]*}/";
$subject = "{token1} foo {token2} bar";
preg_match_all($pattern, $subject, $matches);
print_r($matches);
?>

output:

Array
(
    [0] => Array
        (
            [0] => {token1}
            [1] => {token2}
        )

)

bruha

8 years ago


To count str_length in UTF-8 string i use

$count = preg_match_all("/[[:print:]\pL]/u", $str, $pockets);

where
[:print:] - printing characters, including space
\pL - UTF-8 Letter
/u - UTF-8 string
other unicode character properties on http://www.pcre.org/pcre.txt

no at bo dot dy

5 years ago


For parsing queries with entities use:



<?php

preg_match_all("/(?:^|(?<=\&(?![a-z]+\;)))([^\=]+)=(.*?)(?:$|\&(?![a-z]+\;))/i",

  $s, $m, PREG_SET_ORDER );

?>

ajeet dot nigam at icfaitechweb dot com

2 years ago


Here http://tryphpregex.com/ is a  php based online regex editor which helps you test your regular expressions with real-time highlighting of regex match on data input.

chuckie

9 years ago


This is a function to convert byte offsets into (UTF-8) character offsets (this is reagardless of whether you use /u modifier:

<?php

function mb_preg_match_all($ps_pattern, $ps_subject, &$pa_matches, $pn_flags = PREG_PATTERN_ORDER, $pn_offset = 0, $ps_encoding = NULL) {
  // WARNING! - All this function does is to correct offsets, nothing else:
  //
  if (is_null($ps_encoding))
    $ps_encoding = mb_internal_encoding();

  $pn_offset = strlen(mb_substr($ps_subject, 0, $pn_offset, $ps_encoding));
  $ret = preg_match_all($ps_pattern, $ps_subject, $pa_matches, $pn_flags, $pn_offset);

  if ($ret && ($pn_flags & PREG_OFFSET_CAPTURE))
    foreach($pa_matches as &$ha_match)
      foreach($ha_match as &$ha_match)
        $ha_match[1] = mb_strlen(substr($ps_subject, 0, $ha_match[1]), $ps_encoding);
    //
    // (code is independent of PREG_PATTER_ORDER / PREG_SET_ORDER)

  return $ret;
  }

?>

7 years ago


i have made up a simple function to extract a number from a string..



I am not sure how good it is, but it works.



It gets only the numbers 0-9, the "-", " ", "(", ")", "."



characters.. This is as far as I know the most widely used characters for a Phone number.



<?php

function clean_phone_number($phone) {

       if (!empty($phone)) {

               //var_dump($phone);

               preg_match_all('/[0-9\(\)+.\- ]/s', $phone, $cleaned);

               foreach($cleaned[0] as $k=>$v) {

                       $ready .= $v;

               }

               var_dump($ready);

               die;

               if (mb_strlen($cleaned) > 4 && mb_strlen($cleaned) <=25) {

                       return $cleaned;

               }

               else {

                       return false;

               }

       }

       return false;

}

?>

spambegone at cratemedia dot com

8 years ago


I found simpleXML to be useful only in cases where the XML was extremely small, otherwise the server would run out of memory (I suspect there is a memory leak or something?). So while searching for alternative parsers, I decided to try a simpler approach. I don't know how this compares with cpu usage, but I know it works with large XML structures. This is more a manual method, but it works for me since I always know what structure of data I will be receiving. 



Essentially I just preg_match() unique nodes to find the values I am looking for, or I preg_match_all to find multiple nodes. This puts the results in an array and I can then process this data as I please.



I was unhappy though, that preg_match_all() stores the data twice (requiring twice the memory), one array for all the full pattern matches, and one array for all the sub pattern matches. You could probably write your own function that overcame this. But for now this works for me, and I hope it saves someone else some time as well.



// SAMPLE XML

<RETS ReplyCode="0" ReplyText="Operation Successful">

  <COUNT Records="14" />

  <DELIMITER value="09" />

  <COLUMNS>PropertyID</COLUMNS>

  <DATA>521897</DATA>

  <DATA>677208</DATA>

  <DATA>686037</DATA>

</RETS>



<?PHP



// SAMPLE FUNCTION

function parse_xml($xml) {

    

    

    // GET DELIMITER (single instance)

    $match_res = preg_match('/<DELIMITER value ?= ?"(.*)" ?\/>/', $xml, $matches);

    if(!empty($matches[1])) {

        $results["delimiter"] = chr($matches[1]);

    } else {

        // DEFAULT DELIMITER

        $results["delimiter"] = "\t";

    }

    unset($match_res, $matches);

    

    

    // GET MULTIPLE DATA NODES (multiple instances)

    $results["data_count"] = preg_match_all("/<DATA>(.*)<\/DATA>/", $xml, $matches);

    // GET MATCHES OF SUB PATTERN, DISCARD THE REST

    $results["data"]=$matches[1];

    unset($match_res, $matches);

    

    // UNSET XML TO SAVE MEMORY (should unset outside the function as well)

    unset($xml);



    // RETURN RESULTS ARRAY

    return $results;

    

    

}



?>

phpnet at sinful-music dot com

10 years ago


Here's some fleecy code to 1. validate RCF2822 conformity of address lists and 2. to extract the address specification (the part commonly known as 'email'). I wouldn't suggest using it for input form email checking, but it might be just what you want for other email applications. I know it can be optimized further, but that part I'll leave up to you nutcrackers. The total length of the resulting Regex is about 30000 bytes. That because it accepts comments. You can remove that by setting $cfws to $fws and it shrinks to about 6000 bytes. Conformity checking is absolutely and strictly referring to RFC2822. Have fun and email me if you have any enhancements!

<?php
function mime_extract_rfc2822_address($string)
{
        //rfc2822 token setup
        $crlf           = "(?:\r\n)";
        $wsp            = "[\t ]";
        $text           = "[\\x01-\\x09\\x0B\\x0C\\x0E-\\x7F]";
        $quoted_pair    = "(?:\\\\$text)";
        $fws            = "(?:(?:$wsp*$crlf)?$wsp+)";
        $ctext          = "[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F" .
                          "!-'*-[\\]-\\x7F]";
        $comment        = "(\\((?:$fws?(?:$ctext|$quoted_pair|(?1)))*" .
                          "$fws?\\))";
        $cfws           = "(?:(?:$fws?$comment)*(?:(?:$fws?$comment)|$fws))";
        //$cfws           = $fws; //an alternative to comments
        $atext          = "[!#-'*+\\-\\/0-9=?A-Z\\^-~]";
        $atom           = "(?:$cfws?$atext+$cfws?)";
        $dot_atom_text  = "(?:$atext+(?:\\.$atext+)*)";
        $dot_atom       = "(?:$cfws?$dot_atom_text$cfws?)";
        $qtext          = "[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F!#-[\\]-\\x7F]";
        $qcontent       = "(?:$qtext|$quoted_pair)";
        $quoted_string  = "(?:$cfws?\"(?:$fws?$qcontent)*$fws?\"$cfws?)";
        $dtext          = "[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F!-Z\\^-\\x7F]";
        $dcontent       = "(?:$dtext|$quoted_pair)";
        $domain_literal = "(?:$cfws?\\[(?:$fws?$dcontent)*$fws?]$cfws?)";
        $domain         = "(?:$dot_atom|$domain_literal)";
        $local_part     = "(?:$dot_atom|$quoted_string)";
        $addr_spec      = "($local_part@$domain)";
        $display_name   = "(?:(?:$atom|$quoted_string)+)";
        $angle_addr     = "(?:$cfws?<$addr_spec>$cfws?)";
        $name_addr      = "(?:$display_name?$angle_addr)";
        $mailbox        = "(?:$name_addr|$addr_spec)";
        $mailbox_list   = "(?:(?:(?:(?<=:)|,)$mailbox)+)";
        $group          = "(?:$display_name:(?:$mailbox_list|$cfws)?;$cfws?)";
        $address        = "(?:$mailbox|$group)";
        $address_list   = "(?:(?:^|,)$address)+";

        //output length of string (just so you see how f**king long it is)
        echo(strlen($address_list) . " ");

        //apply expression
        preg_match_all("/^$address_list$/", $string, $array, PREG_SET_ORDER);

        return $array;
};
?>

mnc at u dot nu

10 years ago


PREG_OFFSET_CAPTURE always seems to provide byte offsets, rather than character position offsets, even when you are using the unicode /u modifier.

elyknosrac at gmail dot com

6 years ago


Using preg_match_all I made a pretty handy function.



<?php



function reg_smart_replace($pattern, $replacement, $subject, $replacementChar = "$$$", $limit = -1)

{

    if (! $pattern || ! $subject || ! $replacement ) { return false; }

    

    $replacementChar = preg_quote($replacementChar);

    

    preg_match_all ( $pattern, $subject, $matches);

    

    if ($limit > -1) {

        foreach ($matches as $count => $value )

        {

            if ($count + 1 > $limit ) { unset($matches[$count]); }

        }

    }

    foreach ($matches[0] as $match) {

        $rep = ereg_replace($replacementChar, $match, $replacement);

        $subject = ereg_replace($match, $rep, $subject);

    }

    

    return $subject;

}

?>



This function can turn blocks of text into clickable links or whatever.  Example:



<?php

reg_smart_replace(EMAIL_REGEX, '<a href="mailto:$$$">$$$</a>', $description)

?>

will turn all email addresses into actual links.



Just substitute $$$ with the text that will be found by the regex.  If you can't use $$$ then use the 4th parameter $replacementChar

stamster at gmail dot com

2 months ago


Be careful with this pattern match and large input buffer on preg_match_* functions.

<?php
$pattern = '/\{(?:[^{}]|(?R))*\}/';

preg_match_all($pattern, $buffer, $matches); 
?>

if $buffer is 80+ KB in size, you'll end up with segfault! 

[89396.588854] php[4384]: segfault at 7ffd6e2bdeb0 ip 00007fa20c8d67ed sp 00007ffd6e2bde70 error 6 in libpcre.so.3.13.1[7fa20c8c3000+3c000]

This is due to the PCRE recursion. This is a known bug in PHP since 2008, but it's source is not PHP itself but PCRE library. 

Rasmus Lerdorf has the answer: https://bugs.php.net/bug.php?id=45735#1365812629

"The problem here is that there is no way to detect run-away regular expressions 
here without huge performance and memory penalties. Yes, we could build PCRE in a 
way that it wouldn't segfault and we could crank up the default backtrack limit 
to something huge, but it would slow every regex call down by a lot. If PCRE 
provided a way to handle this in a more graceful manner without the performance 
hit we would of course use it."

matt at lvl99 dot com

5 months ago


I had been crafting and testing some regexp patterns online using the tools Regex101 and a `preg_match_all()` tester and found that the regexp patterns I wrote worked fine on them, just not in my code.

My problem was not double-escaping backslash characters:

<?php
// Input test
$input = "\"something\",\"something here\",\"some\nnew\nlines\",\"this is the end\"";

// Work with online regexp testers, doesn't work in PHP
preg_match_all( "/(?:,|^)(?<!\\)\".*?(?<!\\)\"(?:(?=,)|$)/s", $input, $matches );

/*
Outputs: NULL
*/

// Works with online regexp testers, does work in PHP
preg_match_all( "/(?:,|^)(?<!\\\\)\".*?(?<!\\\\)\"(?:(?=,)|$)/s", $input, $matches );

/*
Outputs:
array(2) {
  [0]=>
  array(4) {
    [0]=>
    string(11) ""something""
    [1]=>
    string(17) ","something here""
    [2]=>
    string(17) ","some
new
lines""
    [3]=>
    string(18) ","this is the end""
  }
  [1]=>
  array(4) {
    [0]=>
    string(9) "something"
    [1]=>
    string(14) "something here"
    [2]=>
    string(14) "some
new
lines"
    [3]=>
    string(15) "this is the end"
  }
}
*/
?>

stas kuryan aka stafox

5 months ago


Here is a awesome online regex editor https://regex101.com/
which helps you test your regular expressions (prce, js, python) with real-time highlighting of regex match on data input.

vojjov dot artem at ya dot ru

11 months ago


// Here is function that allows you to preg_match_all array of patters

function getMatches($pattern, $subject) {
    $matches = array();

    if (is_array($pattern)) {
        foreach ($pattern as $p) {
            $m = getMatches($p, $subject);

            foreach ($m as $key => $match) {
                if (isset($matches[$key])) {
                    $matches[$key] = array_merge($matches[$key], $m[$key]);    
                } else {
                    $matches[$key] = $m[$key];
                }
            }
        }
    } else {
        preg_match_all($pattern, $subject, $matches);
    }

    return $matches;
}

$patterns = array(
    '/<span>(.*?)<\/span>/',
    '/<a href=".*?">(.*?)<\/a>/'
);

$html = '<span>some text</span>';
$html .= '<span>some text in another span</span>';
$html .= '<a href="path/">here is the link</a>';
$html .= '<address>address is here</address>';
$html .= '<span>here is one more span</span>';

$matches = getMatches($patterns, $html);

print_r($matches); // result is below

/*
Array
(
    [0] => Array
        (
            [0] => <span>some text</span>
            [1] => <span>some text in another span</span>
            [2] => <span>here is one more span</span>
            [3] => <a href="path/">here is the link</a>
        )

    [1] => Array
        (
            [0] => some text
            [1] => some text in another span
            [2] => here is one more span
            [3] => here is the link
        )

)
*/

marc

3 years ago


Better use preg_replace to convert text in a clickable link with tag <a> 

$html = preg_replace('"\b(http://\S+)"', '<a href="$1">$1</a>', $text);

satyavvd at ymail dot com

4 years ago


Extract fields out of csv string : ( since before php5.3 you can't use str_getcsv function ) 

Here is the regex :



<?php



$csvData = <<<EOF

10,'20',"30","'40","'50'","\"60","70,80","09\\/18,/\"2011",'a,sdfcd'

EOF



$reg = <<<EOF

/

    (

        (

            ([\'\"])

            (

               ( 

                [^\'\"]

                |

                (\\\\.)

               )*

            )

            (\\3)

            |

            (

                [^,]

                |

                (\\\\.)

            )*

    ),)

    /x

EOF;



preg_match_all($reg,$csvData,$matches);



// to extract csv fields

print_r($matches[2]);

?>

royaltm75 at gmail dot com

6 years ago


I have received complains, that my html2a() code (see below) doesn't work in some cases. 
It is however not the problem with algorithm or procedure, but with PCRE recursive stack limits.

If you use recursive PCRE (?R) you should remember to increase those two ini settings:

ini_set('pcre.backtrack_limit', 10000000);
ini_set('pcre.recursion_limit', 10000000);

But be warned: (from php.ini)

;Please note that if you set this value to a high number you may consume all
;the available process stack and eventually crash PHP (due to reaching the
;stack size limit imposed by the Operating System).

I have written this example mainly to demonstrate the power of PCRE LANGUAGE, not the power of it's implementation  :) 

But if you like it, use it, of course on your own risk.

royaltm75 at NOSPAM dot gmail dot com

7 years ago


The power of pregs is limited only by your *imagination* :)
I wrote this html2a() function using preg recursive match (?R) which provides quite safe and bulletproof html/xml extraction:
<?php
function html2a ( $html ) {
  if ( !preg_match_all( '
@
\<\s*?(\w+)((?:\b(?:\'[^\']*\'|"[^"]*"|[^\>])*)?)\>
((?:(?>[^\<]*)|(?R))*)
\<\/\s*?\\1(?:\b[^\>]*)?\>
|\<\s*(\w+)(\b(?:\'[^\']*\'|"[^"]*"|[^\>])*)?\/?\>
@uxis', $html = trim($html), $m, PREG_OFFSET_CAPTURE | PREG_SET_ORDER) )
    return $html;
  $i = 0;
  $ret = array();
  foreach ($m as $set) {
    if ( strlen( $val = trim( substr($html, $i, $set[0][1] - $i) ) ) )
      $ret[] = $val;
    $val = $set[1][1] < 0 
      ? array( 'tag' => strtolower($set[4][0]) )
      : array( 'tag' => strtolower($set[1][0]), 'val' => html2a($set[3][0]) );
    if ( preg_match_all( '
/(\w+)\s*(?:=\s*(?:"([^"]*)"|\'([^\']*)\'|(\w+)))?/usix
', isset($set[5]) && $set[2][1] < 0
  ? $set[5][0]
  : $set[2][0]
  ,$attrs, PREG_SET_ORDER ) ) {
      foreach ($attrs as $a) {
        $val['attr'][$a[1]]=$a[count($a)-1];
      }
    }
    $ret[] = $val;
    $i = $set[0][1]+strlen( $set[0][0] );
  }
  $l = strlen($html);
  if ( $i < $l )
    if ( strlen( $val = trim( substr( $html, $i, $l - $i ) ) ) )
      $ret[] = $val;
  return $ret;
}
?>

Now let's try it with this example: (there are some really nasty xhtml compliant bugs, but ... we shouldn't worry)

<?php
$html = <<<EOT
some leftover text...
     < DIV class=noCompliant style = "text-align:left;" >
... and some other ...
< dIv > < empty>  </ empty>
  <p> This is yet another text <br  >
     that wasn't <b>compliant</b> too... <br   />
     </p>
 <div class="noClass" > this one is better but we don't care anyway </div ><P>
    <input   type= "text"  name ='my "name' value  = "nothin really." readonly>
end of paragraph </p> </Div>   </div>   some trailing text 
EOT;

$a = html2a($html);
//now we will make some neat html out of it
echo a2html($a);

function a2html ( $a, $in = "" ) {
  if ( is_array($a) ) {
    $s = "";
    foreach ($a as $t)
      if ( is_array($t) ) {
        $attrs=""; 
        if ( isset($t['attr']) )
          foreach( $t['attr'] as $k => $v )
            $attrs.=" ${k}=".( strpos( $v, '"' )!==false ? "'$v'" : "\"$v\"" );
        $s.= $in."<".$t['tag'].$attrs.( isset( $t['val'] ) ? ">\n".a2html( $t['val'], $in."  " ).$in."</".$t['tag'] : "/" ).">\n";
      } else
        $s.= $in.$t."\n";
  } else {
    $s = empty($a) ? "" : $in.$a."\n";
  }
  return $s;
}
?>
This produces:
some leftover text...
<div class="noCompliant" style="text-align:left;">
  ... and some other ...
  <div>
    <empty>
    </empty>
    <p>
      This is yet another text
      <br/>
      that wasn't
      <b>
        compliant
      </b>
      too...
      <br/>
    </p>
    <div class="noClass">
      this one is better but we don't care anyway
    </div>
    <p>
      <input type="text" name='my "name' value="nothin really." readonly="readonly"/>
      end of paragraph
    </p>
  </div>
</div>
some trailing text

MonkeyMan

7 years ago


Here is a way to match everything on the page, performing an action for each match as you go. I had used this idiom in other languages, where its use is customary, but in PHP it seems to be not quite as common.

<?php
function custom_preg_match_all($pattern, $subject)
{
    $offset = 0;
    $match_count = 0;
    while(preg_match($pattern, $subject, $matches, PREG_OFFSET_CAPTURE, $offset))
    {
        // Increment counter
        $match_count++;
    
        // Get byte offset and byte length (assuming single byte encoded)
        $match_start = $matches[0][1];
        $match_length = strlen(matches[0][0]);

        // (Optional) Transform $matches to the format it is usually set as (without PREG_OFFSET_CAPTURE set)
        foreach($matches as $k => $match) $newmatches[$k] = $match[0];
        $matches = $new_matches;
    
        // Your code here
        echo "Match number $match_count, at byte offset $match_start, $match_length bytes long: ".$matches[0]."\r\n";
            
        // Update offset to the end of the match
        $offset = $match_start + $match_length;
    }

    return $match_count;
}
?>

Note that the offsets returned are byte values (not necessarily number of characters) so you'll have to make sure the data is single-byte encoded. (Or have a look at paolo mosna's strByte function on the strlen manual page).
I'd be interested to know how this method performs speedwise against using preg_match_all and then recursing through the results.

DarkSide

2 years ago


This is very useful to combine matches:
$a = array_combine($matches[1], $matches[2]);

dolbegraeb

8 years ago


please note, that the function of "mail at SPAMBUSTER at milianw dot de" can result in invalid xhtml in some cases. think i used it in the right way but my result is sth like this:

<img src="./img.jpg" alt="nice picture" />foo foo foo foo </img>

correct me if i'm wrong. 
i'll see when there's time to fix that. -.-

phektus at gmail dot com

8 years ago


If you'd like to include DOUBLE QUOTES on a regular expression for use with preg_match_all, try ESCAPING THRICE, as in: \\\"

For example, the pattern:
'/<table>[\s\w\/<>=\\\"]*<\/table>/'

Should be able to match:
<table>
<row>
<col align="left" valign="top">a</col>
<col align="right" valign="bottom">b</col>
</row>
</table>
.. with all there is under those table tags.

I'm not really sure why this is so, but I tried just the double quote and one or even two escape characters and it won't work. In my frustration I added another one and then it's cool.

sledge NOSPAM

7 years ago


Perhaps you want to find the positions of all anchor tags.  This will return a two dimensional array of which the starting and ending positions will be returned.

<?php
function getTagPositions($strBody)
{
    define(DEBUG, false);
    define(DEBUG_FILE_PREFIX, "/tmp/findlinks_");
    
    preg_match_all("/<[^>]+>(.*)<\/[^>]+>/U", $strBody, $strTag, PREG_PATTERN_ORDER);
    $intOffset = 0;
    $intIndex = 0;
    $intTagPositions = array();

    foreach($strTag[0] as $strFullTag) {
        if(DEBUG == true) {
            $fhDebug = fopen(DEBUG_FILE_PREFIX.time(), "a");
            fwrite($fhDebug, $fulltag."\n");
            fwrite($fhDebug, "Starting position: ".strpos($strBody, $strFullTag, $intOffset)."\n");
            fwrite($fhDebug, "Ending position: ".(strpos($strBody, $strFullTag, $intOffset) + strlen($strFullTag))."\n");
            fwrite($fhDebug, "Length: ".strlen($strFullTag)."\n\n");
            fclose($fhDebug);
        }
        $intTagPositions[$intIndex] = array('start' => (strpos($strBody, $strFullTag, $intOffset)), 'end' => (strpos($strBody, $strFullTag, $intOffset) + strlen($strFullTag)));
        $intOffset += strlen($strFullTag);
        $intIndex++;
    }
    return $intTagPositions;
}

$strBody = 'I have lots of <a href="http://my.site.com">links</a> on this <a href="http://my.site.com">page</a> that I want to <a href="http://my.site.com">find</a> the positions.';

$strBody = strip_tags(html_entity_decode($strBody), '<a>');
$intTagPositions = getTagPositions($strBody);
print_r($intTagPositions);

/*****
Output:

Array ( 
    [0] => Array ( 
        [start] => 15 
        [end] => 53 ) 
    [1] => Array ( 
        [start] => 62 
        [end] => 99 ) 
    [2] => Array ( 
        [start] => 115 
        [end] => 152 )
 ) 
*****/
?>

fseverin at free dot fr

3 years ago


As I intended to create for my own purpose a clean PHP class to act on XML files, combining the use of DOM and simplexml functions, I had that small problem, but very annoying, that the offsets in a path is not numbered the same in both. 



That is to say, for example, if i get a DOM xpath object it appears like:

/ANODE/ANOTHERNODE/SOMENODE[9]/NODE[2]

and as a simplexml object would be equivalent to:

ANODE->ANOTHERNODE->SOMENODE[8]->NODE[1]



So u see what I mean? I used preg_match_all to solve that problem, and finally I got this after some hours of headlock (as I'm french the names of variables are in French sorry), hoping it could be useful to some of you:



<?php

function decrease_string($string)

    {

        /* retrieve all occurrences AND offsets of numbers in the original string: */



        preg_match_all("/[0-9]+/",$chaine,$out,PREG_OFFSET_CAPTURE);

            for($i=0;$i<sizeof($out[0]);$i++)

            {

                $longueurnombre = strlen((string)$out[0][$i][0]);

                $taillechaine = strlen($chaine);

                // cut the string in 3 pieces

                $debut = substr($chaine,0,$out[0][$i][1]);

                $milieu = ($out[0][$i][0])-1;

                $fin = substr($chaine,$out[0][$i][1]+$longueurnombre,$taillechaine);

                 /* if it's 10,100,1000, the problem is that the string gets shorter and it shifts all the offsets, so we have to decrease them of 1 */

                 if(preg_match('#[1][0]+$#', $out[0][$i][0]))

                 {

                    for($j = $i+1;$j<sizeof($out[0]);$j++)

                    {

                        $out[0][$j][1] = $out[0][$j][1] -1;

                    }

                 }

                $chaine = $debut.$milieu.$fin;

            }

        return $chaine;

    }

?>

avengis at gmail dot com

6 years ago


The next function works with almost any complex xml/xhtml string



<?php

/**

* Find and close unclosed xml tags

**/

function close_tags($text) {

    $patt_open    = "%((?<!</)(?<=<)[\s]*[^/!>\s]+(?=>|[\s]+[^>]*[^/]>)(?!/>))%";

    $patt_close    = "%((?<=</)([^>]+)(?=>))%";

    if (preg_match_all($patt_open,$text,$matches))

    {

        $m_open = $matches[1];

        if(!empty($m_open))

        {

            preg_match_all($patt_close,$text,$matches2);

            $m_close = $matches2[1];

            if (count($m_open) > count($m_close))

            {

                $m_open = array_reverse($m_open);

                foreach ($m_close as $tag) $c_tags[$tag]++;

                foreach ($m_open as $k => $tag)    if ($c_tags[$tag]--<=0) $text.='</'.$tag.'>';

            }

        }

    }

    return $text;

}

?>

mr davin

8 years ago


<?php
// Returns an array of strings where the start and end are found
    function findinside($start, $end, $string) {
        preg_match_all('/' . preg_quote($start, '/') . '([^\.)]+)'. preg_quote($end, '/').'/i', $string, $m);
        return $m[1];
    }
    
    $start = "mary has";
    $end = "lambs.";
    $string = "mary has 6 lambs. phil has 13 lambs. mary stole phil's lambs. now mary has all the lambs.";

    $out = findinside($start, $end, $string);

    print_r ($out);

/* Results in 
(
    [0] =>  6 
    [1] =>  all the 
)
*/ 
?>

preg_match_all

Description

Parameters

Return Values

Changelog

Examples

See Also

User Contributed Notes