Getting file extension using pattern matching in python

Question

I am trying to find the extension of a file, given its name as a string. I know I can use the function os.path.splitext but it does not work as expected in case

Answer 1

Continuing from phihags answer to generic remove all double or triple extensions such as CropQDS275.jpg.aux.xml use while '.' in:

tempfilename, file_extension = os.path.splitext(filename)
while '.' in tempfilename:
     tempfilename, tempfile_extension = os.path.splitext(tempfilename)
     file_extension = tempfile_extension + file_extension