Beefy Boxes and Bandwidth Generously Provided by pair Networks
Pathologically Eclectic Rubbish Lister

Re: regex alternation

by keszler (Priest)
on Sep 30, 2011 at 10:24 UTC ( #928737=note: print w/ replies, xml ) Need Help??

in reply to regex alternation

Why capture the closing single-quote? If you don't need it the alternation is unnecessary overhead. qr<^in directory '/directory/tmp(/\..*)?'$> would be better in that case. Also, if you're not planning to do anything with $1 after the match then there's no need to capture at all: qr<^in directory '/directory/tmp(?:/\..*)?'$>

For overall regex performance it's hard - for me anyway - to determine without knowing what the non-matching data looks like. In general you want the non-matching tests to fail as quickly as possible. (Your anchoring "in directory" to the start of the string is good for that.)

update - moritz's prefix method is even better

Comment on Re: regex alternation
Select or Download Code

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://928737]
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others surveying the Monastery: (8)
As of 2015-11-25 15:32 GMT
Find Nodes?
    Voting Booth?

    What would be the most significant thing to happen if a rope (or wire) tied the Earth and the Moon together?

    Results (681 votes), past polls