On Aug 9, 5:06 pm, Steven D'Aprano <st...@remove-this- cybersource.com.au> wrote: > On Sun, 09 Aug 2009 12:26:54 -0700, Douglas Alan wrote: > > A friend of mine is just learning Python, and he's a bit tweaked about > > how unrecognized escape sequences are treated in Python. > ... > > In any case, I think my friend should mellow out a bit, but we both > > consider this something of a wart. He's just more wart-phobic than I am. > > Is there any way that this behavior can be considered anything other > > than a wart? Other than the unconvincing claim that you can use this > > "feature" to save you a bit of typing sometimes when you actually want a > > backslash to be in your string? > > I'd put it this way: a backslash is just an ordinary character, except > when it needs to be special. So Python's behaviour is "treat backslash as > a normal character, except for these exceptions" while the behaviour your > friend wants is "treat a backslash as an error, except for these > exceptions". > > Why should a backslash in a string literal be an error?
Because the behavior of \ in a string is context-dependent, which means a reader can't know if \ is a literal character or escape character without knowing the context, and it means an innocuous change in context can cause a rather significant change in \. IOW it's an error-prone mess. It would be better if Python (like C) treated \ consistently as an escape character. (And in raw strings, consistently as a literal.) It's kind of a minor issue in terms of overall real-world importance, but in terms of raw unPythonicness this might be the worst offense the language makes. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
