Head and tail in one line

Question

Is there a pythonic way to unpack a list in the first element and the \"tail\" in a single command?

For example:

>> head, tail = **some_magic a         


        

Answer 1

Building on the Python 2 solution from @GarethLatty, the following is a way to get a single line equivalent without intermediate variables in Python 2.

t=iter([1, 1, 2, 3, 5, 8, 13, 21, 34, 55]);h,t = [(h,list(t)) for h in t][0]

If you need it to be exception-proof (i.e. supporting empty list), then add:

t=iter([]);h,t = ([(h,list(t)) for h in t]+[(None,[])])[0]

If you want to do it without the semicolon, use:

h,t = ([(h,list(t)) for t in [iter([1,2,3,4])] for h in t]+[(None,[])])[0]