Print a string minus 3 characters

BabeWalls

Hi,

I have a variable: %img_path% which print something like: gallery/c/_thb_catherine_bell_001.jpg

I want to use this to include a file with the same name but a different extension.

i.e the file i want to include is: gallery/c/_thb_catherine_bell_001.cmt

The way that I can think of to do this is to subtract 3 characters form the string and then add "cmt" to it.

Anyone know how to do this?

kamy99

You can use regular expression to achieve this:

$NewName= $img_path;
echo ereg_replace (".jpg", ".cmt", $NewName);

Hope this helps

saintp

It would almost certainly be faster (and would work for .gifs, .tifs, etc., as well) to do:

$new_name = substr($img_path, 0, -3) . "cmt";

BabeWalls

Thanks for your help, for some reason I couldn't get the second one to work but the first one is fine.

Why would the second one be quicker? Just because it uses less characters?

saintp

The first one is slower because regular expressions have a lot of overhead. If you're going to use that method, I'd use preg_replace() instead of ereg_replace(), again for speed. As they note on php.net, "preg_replace(), which uses a Perl-compatible regular expression syntax, is often a faster alternative to ereg_replace()."

Of course, if you're using PHP < 4.2.0, Perl-style regex (PCRE) isn't enabled by default, so I'd just go with Extended regex (ereg_replace()) in lieu of recompiling PHP.

BabeWalls

Thanks for the very useful info.

I have got the substr version wrking now so that is the one which I am using.

Let me know if preg is faster than substr.

Thanks again 🙂

Arc

it doesnt matter which is faster.. the difference in speed is probably 1 nano second...jeez