Should i Use regexp or string functions

Quick answer: substr is ALWAYS faster

but....

If a pattern is always fixed then using substr will be faster than a regex, but if a pattern is variable then using a regex will be a lot less error prone than messing about with substr.

You should not be worrying about "which one is going to be quicker" because the difference in execution time is tiny - a fraction of a millisecond. Worry about using the right tool for the job instead.

In terms of speed, your MySQL database will have a bigger impact than substr/regex and your customer's ADSL line will have the biggest impact of all because it is usually the slowest component in the whole chain.

Ok. Thanks bportlock!

Obviously I don't know the videoid.

Could you please tell me how would I take the id using substr?
having this pattern:

.....youtube.com/v/videoid&...


Would substring help me to get couple of these if there were more of them in a string?

If not what code should i use as far as regexp is considered?

Please post a sample of your test data.  We can help you isolate the information you need.  You may want to use preg_match_all()
http://php.net/manual/en/function.preg-match-all.php

I agree with Brian's characterization that substr() is faster than REGEX.  At the same time, I expect that speed does not matter here.  The CPU is about 100,000 times faster than the disk drives (give or take a few orders of magnitude) so optimizing any purely-CPU operation like string manipulation is milking a mouse.  A lot of effort for very little result.  If you have a performance problem it will always be in the I/O subsystem.  In web sites that means the data base.

Should have added

http://www.php.net/preg_match_all

Thanks!

I used this:

$videoText = '"<http://www.youtube.com/v/YLwZwheyeEc&setting=1>"';

if((bool)preg_match_all( '#youtube\.com/v/([^&]+)&amp#s',$videoText,$matches)){//w{3}\.youtube\.com\/v\/([A-Za-z0-9]{9,12})>$
            print_r($matches);
      }

And result is
Array ( [0] => Array ( [0] => youtube.com/v/YLwZwheyeEc& ) [1] => Array ( [0] => YLwZwheyeEc ) )

I don't want anything else than videoid how do i do that??
so i want to get rid of matches like [0]

I used this code sorry

$videoText = '"<http://www.youtube.com/v/YLwZwheyeEc&setting=1>"';

if((bool)preg_match_all( '#youtube\.com/v/([^&]+)&amp#s',$videoText,$matches)){
            print_r($matches);
      }

"so i want to get rid of matches like [0]"

$matches[0] is always present, just ignore it. The results are always in $matches[1] onwards depending on the preg options you select