[Baypiggies] Discussion for newbies/beginner night talks
zia at cruzio.com
Sat Feb 10 09:42:21 CET 2007
On Feb 10, 2007, at 12:27 AM, Doug Landauer wrote:
> For what it's worth, here's my version. It was inspired by Hal
> Fulton's "margin" method from his Ruby book. It works at runtime, and
> isn't as strict as the cookbook example that Michael Bernstein
> mentioned (
> http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/145672 ), but
> it's short and a bit easier to use (less cluttered-looking at usage
> site) than Chad's more efficient compile-time version.
> import re
> undent_pat = re.compile( r"(?m)^\s*\S(.*)$", re.M )
> def undent (str):
> return undent_pat.sub( r'\1', str.rstrip() )
Always happens just *after* I post ...
I merged a couple of versions of that pattern, and now the initial (?m)
Removing it makes the pattern easier to understand:
undent_pat = re.compile( r"^\s*\S(.*)$", re.M )
With the M (multiline) mode, ^ matches beginning of any line in the
string, and $ matches the ends of them.
So you can use an even shorter version:
def undent (str):
return re.sub( r'(?m)^\s*\S(.*)$', r'\1', str.rstrip() )
if you don't care about the regex getting recompiled at each usage.
-- Doug L.
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