On Monday 06 November 2006 01:08, Alan Gauld wrote: > While using a dictionary is probably overkill, so is a regex.
No, in this case it's absolutely the right choice. > A simple string holding all characters and an 'in' test would probably > be both easier to read and faster. I'm stunned you think this. It's precisely this sort of naivete that baffles me with regard to regexes. > Which kind of illustrates the point of the thread I think! :-) Actually, no, it doesn't. A regex compiles to a jump table, and executes as a statemachine. (That or the implementation in the library is crap, and I don't believe for a second python would be that dumb) Given you can compile the regex and use it over and over again (as was the context the example code (isplain) was executed in) using a regex is absolutely the best way. I'd be extremely surprised if you could get your suggested approach faster. I also doubt it would actually be clearer, and in this case, that's MUCH more important. (heck, that's the reason regexes are useful - compact clear representations of a lexical structure that you want to check a string matches rather than obfuscated by the language doing the checking) * ^[0-9A-Za-z_.-]*$ Is a very simple pattern, and as a result an extremely simple specification. If any developer has a problem with that sort of pattern, they really need to go away and learn regexes, since they're missing important tools. (which shouldn't be over used). I'm serious, if you think ^[0-9A-Za-z_.-]*$ is unclear and complex, go away and relearn regexes. Michael. _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
