a little about regex
Ant
antroy at gmail.com
Wed Oct 18 11:05:24 EDT 2006
Rob Wolfe wrote:
...
> def filter(adr): # note that "filter" is a builtin function also
> import re
>
> allow = re.compile(r'.*(?<!\.com)\.my(>|$)') # negative lookbehind
> deny = re.compile(r'.*\.com\.my(>|$)')
> cnt = 0
> if deny.search(adr): cnt += 1
> if allow.search(adr): cnt += 1
> return cnt
Which makes the 'deny' code here redundant so in this case the function
could be reduced to:
import re
def allow(adr): # note that "filter" is a builtin function also
allow = re.compile(r'.*(?<!\.com)\.my(>|$)') # negative lookbehind
if allow.search(adr):
return True
return False
Though having the explicit allow and deny expressions may make what's
going on clearer than the fairly esoteric negative lookbehind.
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