On Jun 13, 6:23 pm, anton <[EMAIL PROTECTED]> wrote: > John Machin <sjmachin <at> lexicon.net> writes: > > > > > On Jun 12, 7:11 pm, anton <[EMAIL PROTECTED]> wrote: > > > Hi, > > > > I want to replace all occourences of " by \" in a string. > > > > But I want to leave all occourences of \" as they are. > > > > The following should happen: > > > > this I want " while I dont want this \" > > ... cut text off > > > > > What you want is: > > > >> import re > > >> text = r'frob this " avoid this \", OK?' > > >>> text > > 'frob this " avoid this \\", OK?' > > >> re.sub(r'(?<!\\)"', r'\"', text) > > frob this \\" avoid this \\", OK?' > > > HTH, > > John > > -- > >http://mail.python.org/mailman/listinfo/python-list > > First.. thanks John. > > The whole problem is discussed in > > http://docs.python.org/dev/howto/regex.html#the-backslash-plague > > in the section "The Backslash Plague" > > Unfortunately this is *NOT* mentioned in the standard > python documentation of the re module.
Yes, and there's more to driving a car in heavy traffic than you will find in the manufacturer's manual. > > Another thing which will always remain strange to me, is that > even if in the python doc of raw string: > > http://docs.python.org/ref/strings.html > > its written: > "Specifically, a raw string cannot end in a single backslash" > > s=r"\\" # works fine > s=r"\" # works not (as stated) > > But both ENDS IN A SINGLE BACKSLASH ! Apply the interpretation that the first case ends in a double backslash, and move on. > > The main thing which is hard to understand is: > > If a raw string is a string which ignores backslashes, > then it should ignore them in all circumstances, Nobody defines a raw string to be a "string that ignores backslashes", so your premise is invalid. > or where could be the problem here (python parser somewhere??). Why r"\" is not a valid string token has been done to death IIRC at least twice in this newsgroup ... Cheers, John -- http://mail.python.org/mailman/listinfo/python-list
