replace all "\" with "\\" python

Question

Does anyone know how replace all \ with \\ in python? Ive tried:

re.sub('\','\\',string)

But it screws it up because of the escape sequence. does anyone know the awnser to my question?

@JBernardo, heh, I just realised an deleted that comment, still why not just use the str method instead of regex? ie. string.replace('\\',r'\\') — John La Rooy
– John La Rooy, Commented Jun 26, 2011 at 22:02
@gnibbler As @Ignacio wrote, probably it isn't OP's real question... Maybe he's having trouble with windows paths or CRLF — JBernardo
– JBernardo, Commented Jun 26, 2011 at 22:10
@JBernardo, ah in that case, telling the OP that '/' works fine (instead of '\') in windows paths may or may not help :) — John La Rooy
– John La Rooy, Commented Jun 26, 2011 at 22:15

bradley.ayers · Accepted Answer · 2011-06-26 22:09:32Z

22

You just need to escape the backslashes in your strings: (also there's no need for regex stuff)

>>> s = "cats \\ dogs"
>>> print s
cats \ dogs
>>> print s.replace("\\", "\\\\")
cats \\ dogs

edited Jun 26, 2011 at 22:09

answered Jun 26, 2011 at 21:41

bradley.ayers

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1 Comment

eric.christensen Over a year ago

This doesn't work. You either need re.sub("\\\\","\\\\\\\\",string) or re.sub(r'\\', r'\\\\', string) because you need to escape each slash twice ... once for the string and once for the regex.

JBernardo · Accepted Answer · 2011-06-26 22:16:15Z

7

you should do:

re.sub(r'\\', r'\\\\', string)

As r'\' is not a valid string

BTW, you should always use raw (r'') strings with regex as many things are done with backslashes.

edited Jun 26, 2011 at 22:16

answered Jun 26, 2011 at 21:43

JBernardo

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3 Comments

eric.christensen Over a year ago

This doesn't work. You either need re.sub("\\\\","\\\\\\\\",string) or re.sub(r'\\', r'\\\\', string) because you need to escape each slash twice ... once for the string and once for the regex.

eric.christensen Over a year ago

Still doesn't work. You are trying to replace a literal \ with the first part of a regex escape for special character, so it complains: "error: unexpected end of regular expression"

JBernardo Over a year ago

@ecounysis You're totally right. I hadn't tried in the interpreter... :(

utdemir · Accepted Answer · 2011-06-26 21:52:12Z

3

You should escape backslashes, and also you don't need regex for this simple operation:

>>> my_string = r"asd\asd\asd\\"
>>> print(my_string)
asd\asd\asd\\
>>> replaced = my_string.replace("\\", "\\\\")
>>> print(replaced)
asd\\asd\\asd\\\\

answered Jun 26, 2011 at 21:52

utdemir

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1 Comment

naman1994 Over a year ago

This does work in the interpreter, but fails when I run in the program. Weird. May be I'm doing something stupid.

eric.christensen · Accepted Answer · 2011-06-26 22:22:22Z

3

You either need re.sub("\\\\","\\\\\\\\",string) or re.sub(r'\\', r'\\\\', string) because you need to escape each slash twice ... once for the string and once for the regex.

>>> whatever = r'z\w\r'
>>> print whatever
z\w\r
>>> print re.sub(r"\\",r"\\\\", whatever)
z\\w\\r
>> print re.sub("\\\\","\\\\\\\\",whatever)
z\\w\\r

edited Jun 26, 2011 at 22:22

answered Jun 26, 2011 at 21:46

eric.christensen

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