separating a file extention

Hello all, Is there any easy and efficient way to separate files extention that vary in size? Some have 3 chars after the dot, some 2, some 1, some 4, some none. Examples: test.zip test.gz test.z test.jpeg test.jpg test (no extention) an have the result returned on a $fext field? I think this can also be done with email domains, returning the string right to the at sign. Thanks again.