11–20 of 55 posts
BenchmarkRegexp 500000 5136 ns/op
BenchmarkStrings 10000000 173 ns/op
Basically a great online tool for testing your regular expressions and stepping through what is actually happening. As soon as you get non-trivial, it's a Godsend.
THE single best ressource to really learn how to deal competently with regex is still Jeffrey Friedl's book "Mastering Regular Expressions". You will profit from it for the rest of your career. (There's also a Regex short reference and a Regex cookbook by O'Reilly...)
Sincere question - is it worth investing time into reading a 500 odd page book for something that I might not use that frequently in my career? From my experience, I've seen that I can get away by just Googling or just experimenting whenever I'm stuck on a regex.
What's a good resource for learning reg exp?
THE single best ressource to really learn how to deal competently with regex is still Jeffrey Friedl's book "Mastering Regular Expressions". You will profit from it for the rest of your career. (There's also a Regex short reference and a Regex cookbook by O'Reilly...)
Sincere question - is it worth investing time into reading a 500 odd page book for something that I might not use that frequently in my career? From my experience, I've seen that I can get away by just Googling or just experimenting whenever I'm stuck on a regex.
I think this would be helpful in many cases in getting people to understand how regexes work. I've seen lots of cases where toolsets designed to help people build regexes end up with them confused when their regex also matches other stuff beyond their test strings.
More concise? Sometimes. Slower? Always. BenchmarkRegexp 500000 5136 ns/op BenchmarkStrings 10000000 173 ns/op http://play.golang.org/p/YT29Ao-tOt
The fact is that despite pithy slogans, there is a sweet spot where a regular expression does the job of matching a string in a clearer fashion than anything else. But that sweet spot is well shy of the theoretical power of regular expressions (especially in Perl!), before which you should further your understanding of a range of parsing techniques before hacking together a baroque regex.
More concise? Sometimes. Slower? Always. BenchmarkRegexp 500000 5136 ns/op BenchmarkStrings 10000000 173 ns/op http://play.golang.org/p/YT29Ao-tOt
Thanks for clarifying. I guess my point was that if you're just matching one email address in a form submission for example, is performance significant?
The problem is when developers that don't know any better build parsers with regular expressions. That's almost always a bad idea.
THE single best ressource to really learn how to deal competently with regex is still Jeffrey Friedl's book "Mastering Regular Expressions". You will profit from it for the rest of your career. (There's also a Regex short reference and a Regex cookbook by O'Reilly...)
Sincere question - is it worth investing time into reading a 500 odd page book for something that I might not use that frequently in my career? From my experience, I've seen that I can get away by just Googling or just experimenting whenever I'm stuck on a regex.
The book doesn't just teach you regex, but the why, how AND the dialects. It gives you an overview over different tools and programming languages and their regex-related functions and methods.
On top, it contains a ton of examples, is very well written (considering the insanely dry and difficult to typeset subject :) and is very polished (I think it's in the 3rd edition by now..)
If you just google or experiment on regex, you usally get bad regex, badly crafted regex, brittle regex and make every single mistake the book prevents you from doing.
It's really one of the most worthwhile books of reading through - it's also an excellent handbook to look things up.
Remember that a lot of commandline tools take in regex too - grep, sed, awk, you name it - it's not just for use in programming languages.
Your favorite editor has regex too.
I simple don't know how people can live without; I'm using regex practically every day.
P.S.: And _after_ reading the book, you will understand why people yell at you when you parse HTML with regex but you will know how to do it anyways and at least not completely badly. ;)
P.P.S: And here's the canonical post to BUT OF COURSE you can parse HTML with regex from stackoverflow.. :) http://stackoverflow.com/questions/4231382/regular-expressio...