Extracting extension from filename in Python

Question

Is there a function to extract the extension from a filename?

Answer 1

try this:

files = ['file.jpeg','file.tar.gz','file.png','file.foo.bar','file.etc']
pen_ext = ['foo', 'tar', 'bar', 'etc']

for file in files: #1
    if (file.split(".")[-2] in pen_ext): #2
        ext =  file.split(".")[-2]+"."+file.split(".")[-1]#3
    else:
        ext = file.split(".")[-1] #4
    print (ext) #5

1. get all file name inside the list
2. splitting file name and check the penultimate extension, is it in the pen_ext list or not?
3. if yes then join it with the last extension and set it as the file's extension
4. if not then just put the last extension as the file's extension
5. and then check it out