Getting OS Error when passing string to pathlib.Path in windows

ghz 15hours ago ⋅ 4 views

How to pass string to pathlib.Path in Python3. I am dynamically passing normal windows path in Path(). But it is throwing error.

the snippet is as below:

src = "C:\Documents\Newsletters\Summer2018.pdf"
rsrc = r"C:\Documents\Newsletters\Summer2018.pdf"
s = pathlib.Path(src)
rs = pathlib.Path(rsrc)

print(s.exists())  #  throws error

print(rs.exists()) # returns True

I want to pass normal string to Path, instead off raw string.

Is there anyway to pass normal string to Path and check for its existence,

How to achieve this in windows?

Answer

The issue arises because in Python, backslashes (\) in normal strings are treated as escape characters, unless the string is prefixed with r (raw string).

Problem with src

In the line:

src = "C:\Documents\Newsletters\Summer2018.pdf"

The \D, \N, etc., are interpreted as escape sequences. For example:

  • \D is not a valid escape sequence, so Python throws an error.
  • \n is treated as a newline character.

Solutions

1. Escape the Backslashes

If you want to use a normal string, you need to escape each backslash (\\):

src = "C:\\Documents\\Newsletters\\Summer2018.pdf"
s = pathlib.Path(src)
print(s.exists())  # Should work

2. Use a Raw String

Raw strings treat backslashes as literal characters:

src = r"C:\Documents\Newsletters\Summer2018.pdf"
s = pathlib.Path(src)
print(s.exists())  # Should work

3. Use os.path.normpath

If you have a string that might contain backslashes, you can normalize it using os.path.normpath to ensure compatibility:

import os
import pathlib

src = "C:/Documents/Newsletters/Summer2018.pdf"  # Forward slashes are safe
src_normalized = os.path.normpath(src)
s = pathlib.Path(src_normalized)
print(s.exists())  # Should work

This method is especially useful when your string uses forward slashes (/), as they are automatically converted to backslashes (\) on Windows.

4. Use Forward Slashes

Forward slashes (/) are automatically interpreted correctly on Windows:

src = "C:/Documents/Newsletters/Summer2018.pdf"
s = pathlib.Path(src)
print(s.exists())  # Should work

Summary

To pass a normal string to Path:

  • Use escaped backslashes (\\) or forward slashes (/).
  • For dynamic strings, consider normalizing them with os.path.normpath.

Example:

import pathlib

src = "C:/Documents/Newsletters/Summer2018.pdf"  # or "C:\\Documents\\Newsletters\\Summer2018.pdf"
s = pathlib.Path(src)
print(s.exists())
#py