Renaming file extension using pathlib (python 3)

Question

I am using windows 10 and winpython. I have a file with a .dwt extension (it is a text file). I want to change the extension of this file to .txt.

My code does not throw any errors, but it does not change the extension.

from pathlib import Path

filename = Path("E:\\seaborn_plot\\x.dwt")

print(filename)

filename_replace_ext = filename.with_suffix('.txt')

print(filename_replace_ext)

Expected results are printed out (as shown below) in winpython's ipython window output:

E:\seaborn_plot\x.dwt

E:\seaborn_plot\x.txt

But when I look for a file with a renamed extension, the extension has not been changed, only the original file exists. I suspect windows file permissions.

Solution 1

You have to actually rename the file not just print out the new name.

1. Use Path.rename()

    from pathlib import Path
    my_file = Path("E:\\seaborn_plot\\x.dwt")
    my_file.rename(my_file.with_suffix('.txt'))
   

Note: To replace the target if it exists use Path.replace()

2. Use os.rename()

    import os
    my_file = 'E:\\seaborn_plot\\x.dwt'
    new_ext = '.txt'
    # Gets my_file minus the extension
    name_without_ext = os.path.splitext(my_file)[0]
    os.rename(my_file, name_without_ext + new_ext)
   

Ref:

1. os.path.splitext(path)
2. PurePath.with_suffix(suffix)

Solution 2

From the docs:

Path.rename(target)

Rename this file or directory to the given target. On Unix, if target exists and is a file, it will be replaced silently if the user has permission. target can be either a string or another path object.

^{pathlib — Object-oriented filesystem paths on docs.python.org}

You could use it like this:

from pathlib import Path


filename = Path("E:\\seaborn_plot\\x.dwt")
filename_replace_ext = filename.with_suffix(".txt")
filename.rename(filename_replace_ext)

Comments

[Eryk Sun]

Path has rename and replace methods, e.g. filename.replace(filename.with_suffix('.txt')). For Unix-like behavior we want replace. In Windows, os.rename or Path.rename raises FileExistsError if the target exists. In Unix, rename will silently replace an existing target.

[alejandro joya cruz]

even-though i name the way it does at unix, it behave the same while directory and user have permissions to replaced.