I am not an expert at regular expression and have a regular expression
^\s?([-*]|\d+[.])\s+
I wonder if anyone has ideas about shortening/optimizing/simplifying the above regular expression?
views:
61answers:
3
+1
A:
As Regexes go, that one is pretty darn short and simple as it is. Does it work as you expect? If so, leave it alone.
Andrew Barber
2010-10-26 04:40:44
oh, ok thanks. I was just wondering if I can somehow simplify that regex so its more readable and easy to understand, whether for me, or someone else looking at it in the future
jiewmeng
2010-10-26 04:44:47
Regexes are among some of the least 'readable' constructs you will find in programming, IMO. They just look strange, especially when you are not very fluent with them :P
Andrew Barber
2010-10-26 04:46:09
+1 Perhaps even the idea of optimizing a regex is little skew?
cottsak
2010-10-26 05:03:56
+1
A:
Why would you want to optimize it? The contents of your regular expressions are already made of nonredundant atoms. You cannot simplify this more…
Benoit
2010-10-26 04:41:45
+1 for using the word 'atoms'. I love that word, used appropriately. Don't ask me why! (oh, and for a correct answer!)
Andrew Barber
2010-10-26 04:47:10
The word “atom” coms from vim documentation on patterns. I did not invent it :)
Benoit
2010-10-26 05:00:23
Oh yeah, I know; that's what I mean. :) Mostly, I'm way overdue for bed and channeling a Care Bear!
Andrew Barber
2010-10-26 05:05:33
+2
A:
You can save one entire character (yay!) by writing:
^\s?([-*]|\d+\.)\s+
Other than that there's not much to do here. If you don't need the contents of the alternation, you could make the group non-capturing and maybe shave a nanosecond or two off by writing
^\s?(?:[-*]|\d+\.)\s+
but that's very probably the most extreme form of premature optimization you can do. Plus, you need more characters...
Tim Pietzcker
2010-10-26 09:45:07
EGADS! +1 for finding the 1-char savings by removing the square brackets; hehe
Andrew Barber
2010-10-26 16:24:02