How can I check the extension of a file?

Question

I'm working on a certain program where I need to do different things depending on the extension of the file. Could I just use this?

if m == *.mp3
   ...
elif m == *.flac
   ...

Disparage

use python re module (regex) for matching – Sade

Does this answer your question? Extracting extension from filename in Python – Santosantonica

Answer 1

Assuming m is a string, you can use endswith:

if m.endswith('.mp3'):
...
elif m.endswith('.flac'):
...

To be case-insensitive, and to eliminate a potentially large else-if chain:

m.lower().endswith(('.png', '.jpg', '.jpeg'))

Summer

ext = m.rpartition('.')[-1]; if ext == will be much more efficient – Consume

@Consume why not use .split('.')[-1]? Or is rpartition really high efficiency? – Croze

@Stevoisiak, I think you misplaced your comment as this solution works even in the case you point out – Tessi

This doesn't account for folder names with periods. C:/folder.jpg is a valid path. You can confirm if it is a file or folder with os.path.isfile(m) – Fast

@Tessi Thanks for pointing that out, I fixed my comment – Fast

This isn't file type cheking, if some one change file format so that can makes bugs in program. – Morganne

Answer 2

os.path provides many functions for manipulating paths/filenames. (docs)

os.path.splitext takes a path and splits the file extension from the end of it.

import os

filepaths = ["/folder/soundfile.mp3", "folder1/folder/soundfile.flac"]

for fp in filepaths:
    # Split the extension from the path and normalise it to lowercase.
    ext = os.path.splitext(fp)[-1].lower()

    # Now we can simply use == to check for equality, no need for wildcards.
    if ext == ".mp3":
        print fp, "is an mp3!"
    elif ext == ".flac":
        print fp, "is a flac file!"
    else:
        print fp, "is an unknown file format."

Gives:

/folder/soundfile.mp3 is an mp3!
folder1/folder/soundfile.flac is a flac file!

Borecole

This method ignores leading periods so /.mp3 is not considered an mp3 file. This is however the way a leading space should be treated. E.g .gitignore is not a file format – Detrital

This doesn't account for folder names with periods. (C:/folder.jpg/file.mp3 is a valid path). You can exclude those with os.path.isfile(m) – Fast

Answer 3

Use pathlib From Python3.4 onwards.

from pathlib import Path
Path('my_file.mp3').suffix == '.mp3'

---

If you are working with folders that contain periods, you can perform an extra check using

Path('your_folder.mp3').is_file() and Path('your_folder.mp3').suffix == '.mp3'

to ensure that a folder with a .mp3 suffix is not interpreted to be an mp3 file.

Murillo

Answer 4

Look at module fnmatch. That will do what you're trying to do.

import fnmatch
import os

for file in os.listdir('.'):
    if fnmatch.fnmatch(file, '*.txt'):
        print file

Punctuation

Answer 5

or perhaps:

from glob import glob
...
for files in glob('path/*.mp3'): 
  do something
for files in glob('path/*.flac'): 
  do something else

Stickybeak

Answer 6

one easy way could be:

import os

if os.path.splitext(file)[1] == ".mp3":
    # do something

os.path.splitext(file) will return a tuple with two values (the filename without extension + just the extension). The second index ([1]) will therefor give you just the extension. The cool thing is, that this way you can also access the filename pretty easily, if needed!

Wunderlich

Answer 7

An old thread, but may help future readers...

I would avoid using .lower() on filenames if for no other reason than to make your code more platform independent. (linux is case sensistive, .lower() on a filename will surely corrupt your logic eventually ...or worse, an important file!)

Why not use re? (Although to be even more robust, you should check the magic file header of each file... How to check type of files without extensions in python? )

import re

def checkext(fname):   
    if re.search('\.mp3$',fname,flags=re.IGNORECASE):
        return('mp3')
    if re.search('\.flac$',fname,flags=re.IGNORECASE):
        return('flac')
    return('skip')

flist = ['myfile.mp3', 'myfile.MP3','myfile.mP3','myfile.mp4','myfile.flack','myfile.FLAC',
     'myfile.Mov','myfile.fLaC']

for f in flist:
    print "{} ==> {}".format(f,checkext(f)) 

Output:

myfile.mp3 ==> mp3
myfile.MP3 ==> mp3
myfile.mP3 ==> mp3
myfile.mp4 ==> skip
myfile.flack ==> skip
myfile.FLAC ==> flac
myfile.Mov ==> skip
myfile.fLaC ==> flac

Bebop

Answer 8

You should make sure the "file" isn't actually a folder before checking the extension. Some of the answers above don't account for folder names with periods. (folder.mp3 is a valid folder name).

---

Checking the extension of a file:

import os

file_path = "C:/folder/file.mp3"
if os.path.isfile(file_path):
    file_extension = os.path.splitext(file_path)[1]
    if file_extension.lower() == ".mp3":
        print("It's an mp3")
    if file_extension.lower() == ".flac":
        print("It's a flac")

Output:

It's an mp3

---

Checking the extension of all files in a folder:

import os

directory = "C:/folder"
for file in os.listdir(directory):
    file_path = os.path.join(directory, file)
    if os.path.isfile(file_path):
        file_extension = os.path.splitext(file_path)[1]
        print(file, "ends in", file_extension)

Output:

abc.txt ends in .txt
file.mp3 ends in .mp3
song.flac ends in .flac

---

Comparing file extension against multiple types:

import os

file_path = "C:/folder/file.mp3"
if os.path.isfile(file_path):
    file_extension = os.path.splitext(file_path)[1]
    if file_extension.lower() in {'.mp3', '.flac', '.ogg'}:
        print("It's a music file")
    elif file_extension.lower() in {'.jpg', '.jpeg', '.png'}:
        print("It's an image file")

Output:

It's a music file

Fast

Answer 9

import os
source = ['test_sound.flac','ts.mp3']

for files in source:
   fileName,fileExtension = os.path.splitext(files)
   print fileExtension   # Print File Extensions
   print fileName   # It print file name

Stolen

Answer 10

#!/usr/bin/python

import shutil, os

source = ['test_sound.flac','ts.mp3']

for files in source:
  fileName,fileExtension = os.path.splitext(files)

  if fileExtension==".flac" :
    print 'This file is flac file %s' %files
  elif  fileExtension==".mp3":
    print 'This file is mp3 file %s' %files
  else:
    print 'Format is not valid'

Tompion

Answer 11

if (file.split(".")[1] == "mp3"):
    print "its mp3"
elif (file.split(".")[1] == "flac"):
    print "its flac"
else:
    print "not compat"

Jehovist

This won't work for files containing multiple .s, for example some.test.file.mp3 – Tapis

You could do [-1] to capture that edge case. – Jehovist

Answer 12

If your file is uploaded then

import os


file= request.FILES['your_file_name']          #Your input file_name for your_file_name
ext = os.path.splitext(file.name)[-1].lower()


if ext=='.mp3':
    #do something

elif ext=='.xls' or '.xlsx' or '.csv':
    #do something

else:
    #The uploaded file is not the required format

Suber

Answer 13

file='test.xlsx'
if file.endswith('.csv'):
    print('file is CSV')
elif file.endswith('.xlsx'):
    print('file is excel')
else:
    print('none of them')

Baskerville

Describe something about your answer will help others to understand easily , refer stackoverflow.com/help/how-to-answer – Melquist

Answer 14

I'm surprised none of the answers proposed the use of the pathlib library.

Of course, its use is situational but when it comes to file handling or stats pathlib is gold.

Here's a snippet:

import pathlib


def get_parts(p: str or pathlib.Path) -> None:
    p_ = pathlib.Path(p).expanduser().resolve()
    print(p_)
    print(f"file name: {p_.name}")
    print(f"file extension: {p_.suffix}")
    print(f"file extensions: {p_.suffixes}\n")


if __name__ == '__main__':
    file_path = 'conf/conf.yml'
    arch_file_path = 'export/lib.tar.gz'

    get_parts(p=file_path)
    get_parts(p=arch_file_path)

and the output:

/Users/hamster/temp/src/pro1/conf/conf.yml
file name: conf.yml
file extension: .yml
file extensions: ['.yml']

/Users/hamster/temp/src/pro1/conf/lib.tar.gz
file name: lib.tar.gz
file extension: .gz
file extensions: ['.tar', '.gz']

Hautegaronne