What's the best way to join an array into a readable list?

Question

I've got an array listing days of the week:

days = ['Monday', 'Tuesday', 'Wednesday']

What's the easiest / best way to output it in a human readable format:

Monday, Tuesday and Wednesday

The best I have is rather ugly:

', '.join(days[:-2]+['']) + ' and '.join(days[-2:])

Answer 1

Why is everyone trying to force-fit this into a single expression?

def comma_separated(lst):
    """
    >>> comma_separated(['a'])
    'a'
    >>> comma_separated(['a', 'b'])
    'a and b'
    >>> comma_separated(['a', 'b', 'c'])
    'a, b and c'
    """
    if len(lst) == 1:
        return lst[0]
    comma_part = ", ".join(lst[:-1])
    return "%s and %s" % (comma_part, lst[-1])

if __name__ == "__main__":
    import doctest
    doctest.testmod()

And remember, this is specific to English (and aside from "and", probably some other Western languages). Other languages have entirely different rules.