def likes(names):
    #your code here
    length = len(names)
    if not names:
        return 'no one likes this'
    if length == 1:
        return '{} likes this'.format(*names)
    if length == 2:
        return '{} and {} like this'.format(*names)
    if length == 3:
        return '{}, {} and {} like this'.format(*names)
    if length >= 4:
        return '{}, {} and {} others like this'.format(names[0], names[1], length-2)

論壇中大神的回復(fù)：

def likes(names):
    n = len(names)
    return {
        0: 'no one likes this',
        1: '{} likes this',
        2: '{} and {} like this',
        3: '{}, {} and {} like this',
        4: '{}, {} and {} others like this',
        }[max(4, n)].format(*names[:3], n-2)