一个老帖子，但可能对未来的读者有所帮助…

如果没有其他原因，我将避免在文件名上使用.lower()，只是为了使您的代码更独立于平台。(linux是区分大小写的，文件名上的.lower()最终肯定会破坏你的逻辑…或者更糟，一个重要的文件!)

为什么不用re?(尽管为了更加健壮，您应该检查每个文件的神奇文件头… 如何检查python中没有扩展名的文件类型?)

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)) 

输出:

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

在检查扩展名之前，您应该确保“文件”实际上不是一个文件夹。上面的一些答案没有说明带句点的文件夹名称。(folder.mp3是一个有效的文件夹名)。

检查文件扩展名:

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")

输出:

It's an mp3

检查文件夹中所有文件的扩展名:

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)

输出:

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

比较多种类型的文件扩展名:

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")

输出:

It's a music file

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

如果你的文件上传了

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

从Python3.4开始使用。

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

如果您正在处理包含句点的文件夹，则可以使用

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

确保后缀为.mp3的文件夹不会被解释为mp3文件。

#!/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'