Efficiently test for positive re.match then use the result?

[elmlish]

Hello all,

I'm currently befuddled as to how to efficiently test for a positive re.
match then use the results of that match in a function.

Mostly what I've seen people do is to first test for the match, and then 
try matching again to get the results.  This would seem to be pretty 
inefficient to me.

I've tried making the match, then sending it to a variable, then testing 
if the variable is good and then finally using it, but this still seems 
overkill.

I'm also trying to use this in list comprehensions, mostly because they 
are kind of fun.  What I've got right now looks something like this.


>>> alist = ['boo','hoo','choo']
>>> [re.match('choo',line) for line in calist if re.match('choo',line)]
[<_sre.SRE_Match object at 0x11e218>]

This is a small test, but what I will be looking for various matches in 
is a large special purpose text file.

Does anyone have input on how something like this _should_ be done?
thanks,


-- 

~elmlish~