PHP Removing part of a dynamic string

JonD · 31 Oct 2006 at 17:27

I have strings like this (URL):

?p1=users&p2=management&orderby=dateregistered&order=DESC&p=2

or

?p1=users&p2=management&p=2&orderby=dateregistered&order=DESC

How would I elimate certain variables from this? such as p?

I need to remove &p=2 (the number can be any number).

How can this be done?

Craig321 · 31 Oct 2006 at 17:30

Go into the script and remove it there? Or do you still need it in the actual script?

JonD · 31 Oct 2006 at 17:41

Well this is the kind of thing i need to do

Code:

$string = $_SESSION['QUERY_STRING'];

$string = removeP($string);

echo '<a href="'.$string.'">Link</a>'

joeyjojo · 31 Oct 2006 at 17:54

There's probably a way of going through the string until it finds "p=" and it then removes that bit plus one character.

Would be easier though to remove it from the url. Isn't there any way of not sending it through the url?

joeyjojo · 31 Oct 2006 at 18:02

Ok working on something gimme a minute

Dj_Jestar · 31 Oct 2006 at 18:03

Code:

$string = preg_replace('/' . preg_quote('&p=', '/') . '\d+/', '', $string);

untested.

JonD · 31 Oct 2006 at 18:19

could you explain that thats doing please?

jd

joeyjojo · 31 Oct 2006 at 18:22

Code:

$fullstring = $_SESSION['QUERY_STRING'];

$position = stripos($fullstring, '&p2='); //finds position of the & in '&p2='

$firstbit = strstr($fullstring, 0, $position); //gives up to the &
$remainder = strstr($fullstring, $position); //gives the rest, including '&p2='

$position2 = stripos($lastbit, '&', 1); //gives the position of the next part

$lastbit = strstr($remainder, $position2); //last bit including &

$newstring = $firstbit . $lastbit; //complete string

Untested, might work

JonD · 31 Oct 2006 at 18:34

Dj_Jestar said:
Code:

$string = preg_replace('/' . preg_quote('&p=', '/') . '\d+/', '', $string);

untested.

That works fine at the moment, cant see any bugs. Im not sure what that preg_quote is doing tho.

joeyjojo · 31 Oct 2006 at 18:36

Dj_Jestar said:
Code:

$string = preg_replace('/' . preg_quote('&p=', '/') . '\d+/', '', $string);

untested.

Not sure. Looks like it would only replace '&p=' with ''.

What does the \d+/ do? All those slashes are confusing.

joeyjojo · 31 Oct 2006 at 18:37

JonD said:
That works fine at the moment, cant see any bugs. Im not sure what that preg_quote is doing tho.

preg_quote puts a backslash in front of anything which would affect the code, to stop it giving errors.

http://us2.php.net/manual/en/function.preg-quote.php

joeyjojo · 31 Oct 2006 at 18:43

Oh I see, you want to get rid of p. As in &p=2.

Dammit, thought you wanted &p2=...

Much harder, as its variable length, so you have to chop it up before the & and before the next &, removing that piece.

Conrad11 · 31 Oct 2006 at 20:06

Try the explode function?

JonD · 31 Oct 2006 at 22:21

joeyjojo said:
Not sure. Looks like it would only replace '&p=' with ''.

What does the \d+/ do? All those slashes are confusing.

Yeh whats is that d+?

What what I have to change if instead of numbers after the p there was letters?

joeyjojo · 31 Oct 2006 at 22:30

JonD said:
What what I have to change if instead of numbers after the p there was letters?

I think it replaces the &d= (edit: thats a p) and the next character with blankness. As long as it's one char it's fine. For a variable number give my less classy thing a go.

Sorry about posting hundreds of times up there

JonD · 31 Oct 2006 at 23:50

doesnt the d remove numbers and replacing the d with a will remove a string?

Dj_Jestar · 1 Nov 2006 at 09:29

\d is the key word for Digits (numbers)

The + indicates there will be one or more occurances. Perhaps changing the pattern to:

Code:

&p=[^&]+

would be better suited as the value could literally be anything the user wishes.

I used preg_quote because I couldn't remember if & is a special char in PCRE

preg_quote simply escapes all special characters in a pattern string.