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can someone tell me what is this? about regular expression

Posted on 2008-10-13
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Last Modified: 2012-05-05
http://fdsawfa.com/iafdqe.html?&page=286

and i want to use the preg match all or any other function
to output for me
286

soo people told me to use
preg_match_all('/(?<=[?&]page=)[^&?]*/',$yourvar,$match)){


can someone tell me exactly what eatch part is?
beacuse i want to know what i am using and not only to use it
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Question by:mgtm3
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5 Comments
 
LVL 8

Assisted Solution

by:nahime
nahime earned 350 total points
ID: 22706343
If you need 286 instead of use regex you can read that value in the GET array:

echo $_GET['page'];

This will output 286
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LVL 8

Accepted Solution

by:
nahime earned 350 total points
ID: 22706380
This applies only if you are trying to get that value from the URL of the script otherwise you have to use that preg_match.
An example is:
<?php
$yourvar = "http://fdsawfa.com/iafdqe.html?&pippo=4&page=286";
preg_match_all('/(?<=[?&]page=)[^&?]*/',$yourvar,$match);
echo $match[0][0];
?>

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LVL 8

Assisted Solution

by:nahime
nahime earned 350 total points
ID: 22706542
The part are:
$yourvar -> The variable containing the querystring
$match -> The variable in which the result of the regex is stored
The regular expression remove from $yourvar everything before the first ?
Remove everything between the first ? and "page="
Remove page=
Remove from the first & after "page=" until the end of string (in the example is not needed but is usefull if the string is something like http://fdsawfa.com/iafdqe.html?&pippo=4&page=286&ghgh=ghgh)

So what remain is only the number of page.
The function return 1 if matched the regex or 0 if not and in the array you have what remain of the string exploded into an array.
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LVL 27

Assisted Solution

by:ddrudik
ddrudik earned 150 total points
ID: 22708420
mgtm3, here's an explanation:
----------------------------------------------------------------------
  (?<=                     look behind to see if there is:
----------------------------------------------------------------------
    [?&]                     any character of: '?', '&'
----------------------------------------------------------------------
    page=                    'page='
----------------------------------------------------------------------
  )                        end of look-behind
----------------------------------------------------------------------
  [^&?]*                   any character except: '&', '?' (0 or more
                           times (matching the most amount possible))
----------------------------------------------------------------------
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LVL 27

Expert Comment

by:ddrudik
ID: 22772246
Thanks for the question and the points.
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