Python slice first and last element in list

Question

Is there a way to slice only the first and last item in a list?

For example; If this is my list:

>>> some_list
[\'1\', \'B\', \'3\', \'D\',          


        

Answer 1

Fun new approach to "one-lining" the case of an anonymously split thing such that you don't split it twice, but do all the work in one line is using the walrus operator, :=, to perform assignment as an expression, allowing both:

first, last = (split_str := a.split("-"))[0], split_str[-1]

and:

first, last = (split_str := a.split("-"))[::len(split_str)-1]

Mind you, in both cases it's essentially exactly equivalent to doing on one line:

split_str = a.split("-")

then following up with one of:

first, last = split_str[0], split_str[-1]
first, last = split_str[::len(split_str)-1]

including the fact that split_str persists beyond the line it was used and accessed on. It's just technically meeting the requirements of one-lining, while being fairly ugly. I'd never recommend it over unpacking or itemgetter solutions, even if one-lining was mandatory (ruling out the non-walrus versions that explicitly index or slice a named variable and must refer to said named variable twice).