Python's RE

[John Mitchell]

On Mon, 5 Jun 2000, Jerome Quelin wrote:

> Python does not support non-greedy quantifiers (ie, *?, +? and {,}?)... In
> fact, Perl is the only language that does, I think. You are to do it another
> way in Python.
> 
> > print re.search(r'\((.+?)\)',
> >'aaa(foo)bbb(bar)asdfsadf',re.S|re.M).groups()

> Replace the (.+?) part of your regexp with ([^)]+) and it should work
> the way I think you want it to work

I'm pretty sure you're wrong, Python *does* support the non-greedy '+'
operator.  In Python 1.5.1:

>>> import re
>>> x=re.compile('a.+?b')
>>> p=x.match('axxxb awoob')
>>> p.group(0)
'axxxb'


The non-greedy ".+?" matches only up to the *first* "b", not the last.
Here's the greedy version:

>>> re.compile('a.+b').match('axxxb awoob').group(0)
'axxxb awoob'


I'd highly recommend switing to non-greedy operators, it's extremly
useful.  Regular expressions tend to be pretty hairy, and using this and
inline comments helps tremendously.


- j


"The opposite of bravery is not cowardice but conformity."
--Robert Anthony