Hans Gruber wrote:

Hi Squeak Fans!

I have a short question regarding regular expressions in Squeak.

I have the following problem:

I have a fileName and I want to cut off its file extension (.jpg, .png etc.). To do this efficiently I wanted to use regular expressions with lookaround.

Using regular expressions may be convenient, it sure as hell isn't efficient. Much easier to use, e.g.,

fileName copyUpToLast: $.

As for efficiency:

[1 to: 10000 do:[:i| 'filename.jpg' matchesRegex: '.+(=?.(jpg|jpeg|png))' ]] timeToRun. => 2222 msecs

[1 to: 10000 do:[:i| 'filename.jpg' copyUpToLast: $. ]] timeToRun. => 30 msecs

So using regexp's is about 80x slower.

Cheers, - Andreas

So let's assume the following:

| fileName | fileName := 'test.jpg'.

fileName matchesRegex: '.+(=?.(jpg|jpeg|png))'

I thought there is a possibility of returning the string without file extension through lookaround.

Do you have any hints for me?

Thanks guys!

Regards, Hans ______________________________________________________ GRATIS für alle WEB.DE-Nutzer: Die maxdome Movie-FLAT! Jetzt freischalten unter http://movieflat.web.de