196
votes

What is the best way to represent a Windows directory, for example "C:\meshes\as"? I have been trying to modify a script but it never works because I can't seem to get the directory right, I assume because of the '\' acting as escape character?

5

5 Answers

281
votes

you can use always:

'C:/mydir'

this works both in linux and windows. Other posibility is

'C:\\mydir'

if you have problems with some names you can also try raw string literals:

r'C:\mydir'

however best practice is to use the os.path module functions that always select the correct configuration for your OS:

os.path.join(mydir, myfile)

From python 3.4 you can also use the pathlib module. This is equivelent to the above:

pathlib.Path(mydir, myfile)

or

pathlib.Path(mydir) / myfile
26
votes

Use the os.path module.

os.path.join( "C:", "meshes", "as" )

Or use raw strings

r"C:\meshes\as"

I would also recommend no spaces in the path or file names. And you could use double backslashes in your strings.

"C:\\meshes\\as.jpg"
23
votes

Yes, \ in Python string literals denotes the start of an escape sequence. In your path you have a valid two-character escape sequence \a, which is collapsed into one character that is ASCII Bell:

>>> '\a'
'\x07'
>>> len('\a')
1
>>> 'C:\meshes\as'
'C:\\meshes\x07s'
>>> print('C:\meshes\as')
C:\meshess

Other common escape sequences include \t (tab), \n (line feed), \r (carriage return):

>>> list('C:\test')
['C', ':', '\t', 'e', 's', 't']
>>> list('C:\nest')
['C', ':', '\n', 'e', 's', 't']
>>> list('C:\rest')
['C', ':', '\r', 'e', 's', 't']

As you can see, in all these examples the backslash and the next character in the literal were grouped together to form a single character in the final string. The full list of Python's escape sequences is here.

There are a variety of ways to deal with that:

  1. Python will not process escape sequences in string literals prefixed with r or R:

    >>> r'C:\meshes\as'
    'C:\\meshes\\as'
    >>> print(r'C:\meshes\as')
    C:\meshes\as
    
  2. Python on Windows should handle forward slashes, too.

  3. You could use os.path.join ...

    >>> import os
    >>> os.path.join('C:', os.sep, 'meshes', 'as')
    'C:\\meshes\\as'
    
  4. ... or the newer pathlib module

    >>> from pathlib import Path
    >>> Path('C:', '/', 'meshes', 'as')
    WindowsPath('C:/meshes/as')
    
0
votes

Use Path:

from pathlib import Path
data_folder = Path("source_data/text_files/")
file_to_open = data_folder / "raw_data.txt"
print(file_to_open.read_text())

Path takes a path-like string and adjusts everything for the current OS, either Windows or Linux. For example, on Linux it would convert all backslashes to forward slashes, and on Windows it would do the reverse.

Full article: Python 3 Quick Tip: The easy way to deal with file paths on Windows, Mac and Linux


My experience:

  • I spent 6 months using os.path.join(...), then switched to normpath(...) then finally switched to Path(...). Having used all three, Path is the best of all worlds.

Advantages of Path over os.path.join(...):

  • Cleaner.
  • Less typing.
  • Easier to read the paths (i.e. more readable).
  • Can join two different paths using / (see above).
  • More modern.

Advantages of path over normpath(...):

  • Can join paths using / rather than having to fall back to os.path.join(...), with nested normpath calls to fix things up.
  • Cleaner.
  • Less typing.
  • Easier to read the paths (i.e. more readable).
  • Less chance of bugs when porting between Linux and Windows.
  • More modern.
-2
votes

Use PowerShell

In Windows, you can use / in your path just like Linux or macOS in all places as long as you use PowerShell as your command-line interface. It comes pre-installed on Windows and it supports many Linux commands like ls command.

If you use Windows Command Prompt (the one that appears when you type cmd in Windows Start Menu), you need to specify paths with \ just inside it. You can use / paths in all other places (code editor, Python interactive mode, etc.).