On Mon, 16 Aug 2010 05:46:17 -0700, Alex Willmer wrote: > On Aug 16, 12:23 pm, Steven D'Aprano <st...@remove-this- > cybersource.com.au> wrote: >> On Sun, 15 Aug 2010 17:36:07 -0700, Alex Willmer wrote: >> > On Aug 16, 1:07 am, Steven D'Aprano <st...@remove-this- >> > cybersource.com.au> wrote: >> >> You're passing re.IGNORECASE (which happens to equal 2) as a count >> >> argument, not as a flag. Try this instead: >> >> >> >>> re.sub(r"python\d\d" + '(?i)', "Python27", t) >> >> 'Python27' >> >> > Basically right, but in-line flags must be placed at the start of a >> > pattern, or the result is undefined. >> >> Pardon me, but that's clearly not correct, as proven by the fact that >> the above example works. > > Undefined includes 'might work sometimes'. I refer you to the Python > documentation: > > "Note that the (?x) flag changes how the expression is parsed. It should > be used first in the expression string, or after one or more whitespace > characters. If there are non-whitespace characters before the flag, the > results are undefined." > http://docs.python.org/library/re.html#regular-expression-syntax
Well so it does. I stand corrected. I note though that even the docs say "should" rather than "must". I wonder whether the documentation author is just being cautious, because I've seen comments on the python-dev list that imply that the current behaviour of flags (that their effect is global to the regex) is supported. E.g.: http://code.activestate.com/lists/python-dev/98681/ At the point that people are seriously considering changing the behaviour of a replacement re engine in order to support the current "undefined" behaviour, perhaps that behaviour isn't quite so undefined and the docs need to be re-written? -- Steven -- http://mail.python.org/mailman/listinfo/python-list
