PHP, remove string using "pattern"

Question

I have the following url which will always have a color variable attached:

http://www.example.com/?new=yes&color=red&shape=square

How would I, using PHP, remove everything at the end; starting at &color, so I am left with the following:

http://www.example.com/?new=yes

What if the order of the parameters differs?

Gumbo
– Gumbo

2011-03-31 18:20:59 +00:00
Commented Mar 31, 2011 at 18:20 — Gumbo
– Gumbo, Commented Mar 31, 2011 at 18:20
They won't. Very few links, this is just for myself.

Keith
– Keith

2011-03-31 18:21:56 +00:00
Commented Mar 31, 2011 at 18:21 — Keith
– Keith, Commented Mar 31, 2011 at 18:21

Jon · Accepted Answer · 2011-03-31 18:23:41Z

3

The literal answer to your question is:

$url = substr($url, 0, strpos($url, '&color='));

However, this is good only for the specific case -- it would probably be a good idea to do something a little more robust. For example, splitting the URL, getting the key/value pairs into an array, removing those you don't want (or removing everything except those you want) and recreating the URL.

answered Mar 31, 2011 at 18:23

Jon

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3 Comments

Keith Over a year ago

Thanks for taking the time to reply, perfect job!

Gumbo Over a year ago

What if the needle is not contained?

Jon Over a year ago

@Gumbo: Bad things happen. But I gathered the impression from the OP's comment that this is throwaway code, and it's hard to argue against a single LOC if that's true.

Dave · Accepted Answer · 2011-03-31 18:25:21Z

2

$url = "http://www.example.com/?new=yes&color=red&shape=square";

$url_parts = explode("&", $url);

$thePartYouWant = $url_parts[0];

answered Mar 31, 2011 at 18:25

Dave

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Comments

Brad Christie · Accepted Answer · 2011-03-31 18:38:44Z

2

I would recommend the combination of parse_url & parse_str. You can also use http_build_url & http_build_str, though these require pecl_http.

edited Mar 31, 2011 at 18:38

answered Mar 31, 2011 at 18:24

Brad Christie

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5 Comments

Keith Over a year ago

And thanks for the reply Brad, will take a look at those functions

Jon Over a year ago

While this approach is what I view as "most correct" (and better than the shameful hack that is my answer), it has a big practical flaw: http_build_url and friends is not built in by default.

Brad Christie Over a year ago

@Jon: Indeed. Part of the PECL lib, though intended as the most "bullet-proof" solution.

Jon Over a year ago

I 'm only saying because the other day I was going to recommend exactly this for another question; when I found out that it wasn't built in and my "example" code was going above 1 screen size on its quest for correctness, I gave up.

Brad Christie Over a year ago

@Jon: I hear ya, I've had those days... ;-)

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