Is there a simpler way to make an English-readable list from strings in a tuple?

I looking over some old code, I had written the function below with a C-style for-loop iterating over a count variable. I then fixed it up with new knowledge, but still am suspicious that there is even a better way to do this.

The function should behave like so:

>>> join_list(['a'])
'a'
>>> join_list(['a', 'b'])
'a or b'
>>> join_list(['a', 'b', 'c'])
'a, b, or c'

The function I have currently:

def join_list(my_list):
    length = len(my_list)
    if length == 1:
        return my_list[0]
    elif length == 2:
        return ' or '.join(my_list)
    else:
        head = ', '.join(my_list[:-1])
        return head + ', or ' + my_list[-1]

Looks pretty good. The only problem I can see is that you're not doing a check to make sure the list is not empty: if it is, then you'll try to access my_list[-1] in the final else clause, which will raise an IndexError.

Hence, I'd simply add a check up front for length == 0 and return '' in that case.

StackExchange Code Review Q#41199, answer score: 8