Lele Gaifax wrote: > Hi all, > > trying out pgcli with Python 3.6.0b2 I got an error related to what seem a > different behaviour, or even a bug, of re.sub(). > > The original intent is to replace spaces within a string with the regular > expression \s+ (see > https://github.com/dbcli/pgcli/blob/master/pgcli/packages/prioritization.py#L11, > ignore the fact that the re.sub() call seem underoptimal). > > With Python 3.5.2 is straightforward: > > $ python3.5 > Python 3.5.2+ (default, Sep 22 2016, 12:18:14) > [GCC 6.2.0 20160927] on linux > Type "help", "copyright", "credits" or "license" for more information. > >>> import re > >>> re.sub(r'\s+', r'\s+', 'foo bar') > 'foo\\s+bar' > > While Python 3.6.0b2 gives: > > $ python3.6 > Python 3.6.0b2+ (default, Oct 11 2016, 08:30:05) > [GCC 6.2.0 20160927] on linux > Type "help", "copyright", "credits" or "license" for more information. > >>> import re > >>> re.sub(r'\s+', r'\s+', 'foo bar') > Traceback (most recent call last): > File "/usr/local/python3.6/lib/python3.6/sre_parse.py", line 945, in > parse_template > this = chr(ESCAPES[this][1]) > KeyError: '\\s' > > During handling of the above exception, another exception occurred: > > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > File "/usr/local/python3.6/lib/python3.6/re.py", line 191, in sub > return _compile(pattern, flags).sub(repl, string, count) > File "/usr/local/python3.6/lib/python3.6/re.py", line 326, in _subx > template = _compile_repl(template, pattern) > File "/usr/local/python3.6/lib/python3.6/re.py", line 317, in > _compile_repl > return sre_parse.parse_template(repl, pattern) > File "/usr/local/python3.6/lib/python3.6/sre_parse.py", line 948, in > parse_template > raise s.error('bad escape %s' % this, len(this)) > sre_constants.error: bad escape \s at position 0 > > Accordingly to the documentation > (https://docs.python.org/3.6/library/re.html#re.sub) “unknown escapes [in > the repl argument] such as \& are left alone”. > > Am I missing something, or is this a regression?
According to https://docs.python.org/dev/library/re.html#re.sub rejection of \s is intentional """ Changed in version 3.6: Unknown escapes consisting of '\' and an ASCII letter now are errors. """ though IMHO the traceback needs a cleanup. -- https://mail.python.org/mailman/listinfo/python-list
