regex's

[Tim Hochberg]

chibaA at TinterlogD.Tcom writes:

> Hi...  I'm having a bit of a brain-tease...  I have the following code
> (example):
> 
> import re
> 
> str = '123'
> if re.compile('1').match(str):
> 	print "matched 1"
> if re.compile('2').match(str):
> 	print "matched 2"
> if re.compile('3').match(str):
> 	print "matched 3"
> 
> -------------------
> 
> I would think that this code would print 'matched 1 matched 2 matched
> 3'...  But in this case, it would only printed "matched 1".  Any
> reasons?  Is there any way to have it print all three (since the
> conditions seem to be true)?

re.match matches from the beginning of the string (e.g.,
re.compile('2').match(str) will only match strings starting with
'2'. What you want is re.search. For example:

#....
if re.compile('2').search(str):
	# ...

You could also use:

#....
if re.search('2', str):
	# ...

However, the former will be faster if you reuse the regular
expression since you can compile it once and reuse the compiled
version.


-tim
 
> Thanks in advance!
> 
> kc.