How to replace or strip an extension from a filename in Python

Question

Is there a built-in function in Python that would replace  or remove  whatever  the extension of a filename  if it has one   Example  print replace extension   home user somefile txt     jpg    In my example   home user somefile txt would become  home user somefile jpg I don t know if it matters  but I need this for a SCons module I m writing   So perhaps there is some SCons specific function I can use    I d like something clean  Doing a simple string replacement of all occurrences of  txt within the string is obviously not clean   This would fail if my filename is somefile txt txt txt

User · Answer

I prefer the following one-liner approach using str.rsplit():

my_filename.rsplit('.', 1)[0] + '.jpg'

Example:

>>> my_filename = '/home/user/somefile.txt'
>>> my_filename.rsplit('.', 1)
>>> ['/home/user/somefile', 'txt']

User · Answer

Another way to do is to use the str rpartition sep  method    For example   filename     home user somefile txt   prefix  sep  suffix    filename rpartition       new filename   prefix     jpg   print new filename

User · Answer

For Python    3 4   from pathlib import Path  filename     home user somefile txt   p   Path filename  new filename   p parent joinpath p stem     jpg     PosixPath   home user somefile jpg   new filename str   str new filename      home user somefile jpg

User · Answer

Try os path splitext it should do what you want   import os print os path splitext   home user somefile txt   0    jpg

User · Answer

I m surprised nobody has mentioned pathlib s with name  This solution works with multiple extensions  i e  it replaces all of the extensions   import pathlib  p   pathlib Path   some path somefile txt   p   p with name p stem  with suffix   jpg

User · Answer

As  jethro said  splitext is the neat way to do it  But in this case  it s pretty easy to split it yourself  since the extension must be the part of the filename coming after the final period   filename     home user somefile txt  print  filename rsplit       1    0         home user somefile    The rsplit tells Python to perform the string splits starting from the right of the string  and the 1 says to perform at most one split  so that e g   foo bar baz  -     foo bar    baz      Since rsplit will always return a non-empty array  we may safely index 0 into it to get the filename minus the extension

User · Answer

Expanding on AnaPana s answer  how to remove an extension using pathlib  Python    3 4     gt  gt  gt  from pathlib import Path   gt  gt  gt  filename   Path   some path somefile txt     gt  gt  gt  filename wo ext   filename with suffix       gt  gt  gt  filename replace ext   filename with suffix   jpg     gt  gt  gt  print filename   some path somefile ext       gt  gt  gt  print filename wo ext   some path somefile   gt  gt  gt  print filename replace ext   some path somefile jpg

User · Answer

Handling multiple extensions In the case where you have multiple extensions this one-liner using pathlib and str replace works a treat  Remove strip extensions  gt  gt  gt  from pathlib import Path  gt  gt  gt  p   Path  quot  path to myfile tar gz quot    gt  gt  gt  extensions    quot  quot  join p suffixes     any python version  gt  gt  gt  str p  replace extensions   quot  quot     path to myfile     python gt  3 9  gt  gt  gt  str p  removesuffix extensions    path to myfile   Replace extensions  gt  gt  gt  p   Path  quot  path to myfile tar gz quot    gt  gt  gt  extensions    quot  quot  join p suffixes   gt  gt  gt  new ext    quot  jpg quot   gt  gt  gt  str p  replace extensions  new ext    path to myfile jpg   If you also want a pathlib object output then you can obviously wrap the line in Path    gt  gt  gt  Path str p  replace  quot  quot  join p suffixes    quot  quot    PosixPath   path to myfile    Wrapping it all up in a function from pathlib import Path from typing import Union  PathLike   Union str  Path    def replace ext path  PathLike  new ext  str    quot  quot   - gt  Path      extensions    quot  quot  join Path path  suffixes      return Path str p  replace extensions  new ext     p   Path  quot  path to myfile tar gz quot   new ext    quot  jpg quot   assert replace ext p  new ext     Path   path to myfile jpg   assert replace ext str p   new ext     Path   path to myfile jpg   assert replace ext p     Path   path to myfile

[python] How to replace (or strip) an extension from a filename in Python?

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