Re: regex to remove all non a-z and spaces

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Re^2: regex to remove all non a-z and spaces by mrborisguy (Hermit) on May 16, 2005 at 02:52 UTC
a question on implementation... would the + make the regex any faster, since it matches more before it substitues? not that it matters at all in a case like this... just wondering, to file away in my "pieces of worthless trivia" section of the brain.	[reply]
Re^3: regex to remove all non a-z and spaces by davidrw (Prior) on May 16, 2005 at 02:57 UTC
I was thinking the same thing as i posted that, and I don't know -- I was actually thinking of posting it as a question.. i guess i'll do that now. Update: I forked this to a new thread: regex internals: quantifiers vs global match	[reply]
Re^4: regex to remove all non a-z and spaces by northwind (Hermit) on May 16, 2005 at 06:08 UTC
Synopsis from forked thread: Yes it does. At least for average and special cases (pathological ones are another matter).	[reply]
Re^2: regex to remove all non a-z and spaces by coldfingertips (Pilgrim) on May 16, 2005 at 02:52 UTC
I'm not good with regexes to any degree but doesn't ^ just mean to match at the beginning of the string? How is this removing everything but a-z and numbers?	[reply]
Re^3: regex to remove all non a-z and spaces by mrborisguy (Hermit) on May 16, 2005 at 02:53 UTC
usually, ^ does mean at the beginning, but the [ and ] make a character class, and a ^ at the beginning of a character class means "not any of these". Update: Oddly enough, it doesn't explicitly say that in perlre. however, it does say You can negate the [::] character classes by prefixing the class name with a '^'. This is a Perl extension.	[reply]
Re^4: regex to remove all non a-z and spaces by coldfingertips (Pilgrim) on May 16, 2005 at 02:57 UTC
So what it's really saying is "s/// anything that is not within our class"? So `s/[^0-9\.-]//g;` would be an example on how to remove any non number (except - and .)?	[reply] [d/l]
Re^5: regex to remove all non a-z and spaces by mrborisguy (Hermit) on May 16, 2005 at 03:01 UTC
Re^6: regex to remove all non a-z and spaces by coldfingertips (Pilgrim) on May 16, 2005 at 03:04 UTC
Re^4: regex to remove all non a-z and spaces by hv (Prior) on May 16, 2005 at 11:02 UTC
Oops, that's a strange omission in the docs (though negating character classes is briefly mentioned in perlrequick and perlretut. Just for the record, it is specifically the negation of POSIX character classes that is a perl extension - `/[^a-z]/` is straight from Henry Spencer's original code. Hugo	[reply] [d/l]