[Python-3000] Raw strings containing \u or \U (original) (raw)

Steven Bethard steven.bethard at gmail.com
Wed May 16 18:55:57 CEST 2007

On 5/16/07, Guido van Rossum <guido at python.org> wrote:

Walter Doerwald, in private mail, reminded me of a third use case for raw strings: docstrings containing example code using backslashes. Here it really seems wrong to interpolate \u and \U.

So this is swaying me towards changing this behavior: r"\u1234" will be a string of length 6, and r"\U00012345" one of length 10.

+1 for making raw strings truly raw (where backslashes don't escape anything) and teaching the re module about the necessary escapes (\u, \n, \r, etc.).

I'm still on the fence about the trailing backslash; I personally prefer to write Windows paths using regular strings and doubled backslashes.

+1 for no escaping of quotes in raw strings. Python provides so many different ways to quote a string, the cases in which you can't just switch to another quoting style are vanishingly small. Examples from the stdlib and their translations::

'\'' --> "'"
'("|\')' --> '''("|')'''
'Can\'t stat' --> "Can't stat"
'(\'[^\']*\'|"[^"]*")?' --> '''('[^']*'|"[^"]*")?'''

Note that allowing trailing backslashes could also clean up stuff in modules like ntpath::

path[-1] in "/\\" --> path[-1] in r"/\"
firstTwo == '\\\\' --> firstTwo == r'\\'

STeVe

I'm not in-sane. Indeed, I am so far out of sane that you appear a tiny blip on the distant coast of sanity. --- Bucky Katt, Get Fuzzy

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