使用正则表达式捕获重复的组

Question

I'm trying to build a comma separated list of the items. The items are made up of what is in the quotes embedded in expression similar to the following two examples.

The list is from a session file, comprising a starting text identifier, followed by a or s to indicate array/string, a number to indicate how many items in the array (0 if there is no array) - here's a couple of examples:

extralistids|a:3:{i:0;s:3:"id1";i:1;s:4:" id2";i:2;s:4:" id3";}
extralistids|s:0:"";

I've got the following preg_match expression but it only captures "id3" - any thoughts what I am doing wrong?

/extralistids.+?(?:{).*?("(.*?)"(?:.*?))+;(?:})/

Answer 1

If you want to use the string extralistids in your pattern then try the below regex.

(?:\bextralistids\||(?<!^)\G)[^"]*\"([^"
]*)"

DEMO

<?php
$mystring =<<<EOT
extralistids|a:3:{i:0;s:3:"id1";i:1;s:4:" id2";i:2;s:4:" id3";}
extralistids|s:0:""
EOT;
$regex = '~(?:\bextralistids\||(?<!^)\G)[^"]*\"([^"
]*)"~';
preg_match_all($regex, $mystring, $matches);
print_r($matches[1]);
?>

Output:

Array
(
    [0] => id1
    [1] =>  id2
    [2] =>  id3
    [3] => 
)