Python replace forward slash with back slash

Question

I have

foo = '/DIR/abc'

and I want to convert it to

bar = '\\MYDIR\data\abc'

So, here's what I do in Python:

>>> foo = '/DIR/abc'
>>> bar = foo.replace(r'/DIR/',r'\\MYDIR\data\')
  File "<stdin>", line 1
    bar = foo.replace(r'/DIR/',r'\\MYDIR\data\')
                                                 ^
SyntaxError: EOL while scanning string literal

If, however, I try to escape the last backslash by entering instead bar = foo.replace(r'/DIR/',r'\\MYDIR\data\\'), then I get this monstrosity:

>>> bar2
'\\\\MYDIR\\data\\\\abc'

Help! This is driving me insane.

possible duplicate of [Python raw literal string](http://stackoverflow.com/questions/3517802/python-raw-literal-string) — nneonneo, Jan 31 '13 at 21:21
**See also:** https://stackoverflow.com/search?q=leaning+toothpick+syndrome — dreftymac, Nov 03 '22 at 18:57

Explosion Pills · Accepted Answer · 2013-01-31T22:40:41.670

6

The second argument should be a string, not a regex pattern:

foo.replace(r'/DIR/', '\\\\MYDIR\\data\\')

edited Jan 31 '13 at 22:40

answered Jan 31 '13 at 21:16

Explosion Pills

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I get `SyntaxError: EOL while scanning string literal` when running your code. – synaptik Jan 31 '13 at 21:19
Woops, sorry. I missed the last `\ ` again, just like you :P – Explosion Pills Jan 31 '13 at 21:20
2

Now the result is `'\\\\MYDIR\\data\\abc'` – synaptik Jan 31 '13 at 21:21
You answer is not correct. The second argument will generate the same SyntaxError because you're trying to end the string with a single backslash, which is treated is the string "\'" – Manfre Jan 31 '13 at 21:24
2

@synaptik If you're seeing that in the python REPL, it prints escaped strings automatically. Try `print '\\\\MYDIR\data\\abc'` to get the value you seek – Explosion Pills Jan 31 '13 at 21:25
@Manfre seems to work fine for me. I tested it out. Also, the string is not ending with a single backslash – Explosion Pills Jan 31 '13 at 21:28
Your edit and my comment crossed. I'm now seeing it with the fix. – Manfre Jan 31 '13 at 21:33
@Manfre yeah it was a dumb copy/paste error by me in the first place – Explosion Pills Jan 31 '13 at 21:35
@ExplosionPills You're actually escaping the `d` in this code, luckily `\d` isn't valid so it doesn't show but you should fix it. – Serdalis Jan 31 '13 at 21:45
@Serdalis I disagree; why add more characters that aren't needed? – Explosion Pills Jan 31 '13 at 21:53
@ExplosionPills You are effectively attempting to escape an invalid character, that in itself is reason enough to add another slash. We aren't working on floppy based machines anymore, your computer can handle a bit of correctness. – Serdalis Jan 31 '13 at 21:58

score 3 · Answer 2 · answered Jan 31 '13 at 21:22

The reason you are encountering this is because of the behavior of the r"" syntax, Taking some explanation from the Python Documentation

r"\"" is a valid string literal consisting of two characters: a backslash and a double quote; r"\" is not a valid string literal (even a raw string cannot end in an odd number of backslashes). Specifically, a raw string cannot end in a single backslash (since the backslash would escape the following quote character).

So you will need to use a normal escaped string for the last argument.

>>> foo = "/DIR/abc"
>>> print foo.replace(r"/DIR/", "\\\\MYDIR\\data\\")
\\MYDIR\data\abc

score 3 · Answer 3 · edited Jun 13 '17 at 16:16

3

I simply put a r in front of / to change the forward slash.

inv_num = line.replace(r'/', '-')

edited Jun 13 '17 at 16:16

Ramesh-X

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answered Jun 13 '17 at 14:55

Wen-Shan Wendy Chow

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score 0 · Answer 4 · answered Jan 31 '13 at 21:23

Two problems:

A raw literal simply cannot end with a single backslash because it is interpreted as escaping the quote character. Therefore, use a regular (non-raw) literal with escapes: '\\\\MYDIR\\data\\'.
When displayed (using the repr style), strings will appear with escapes. Therefore, '\\\\' only has two actual backslashes. So, '\\\\MYDIR\\data\\\\abc' is really \\MYDIR\data\\abc.

score 0 · Answer 5 · answered Apr 27 '22 at 06:40

0

path=path.replace(r"/","\") will replace path=C:/folder with path=C:\folder

answered Apr 27 '22 at 06:40

Andy

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As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Apr 27 '22 at 06:43

Python replace forward slash with back slash

5 Answers5