Python:如何运行没有参数的函数？

Question

编写一个函数 music_func 接受 3 个参数 music type, music group, vocalist 并将它们全部打印出来，如下例所示。

如果用户未提供任何输入，该函数应采用这些参数值:“Classic Rock”、“The Beatles”、“Freddie Mercury”。

例如:

输入:

Alternative Rock,Pearl Jam,Chris Cornell

输出:

The best kind of music is Alternative Rock
The best music group is Pearl Jam
The best lead vocalist is Chris Cornell

Note : The print statements will go inside the music_func(). For example: print("The best kind of music is" + ...)

#definition for music_func goes here
def music_func(a,b,c):
    if a is None or b is None or c is None:
        print("The best kind of music is Classic Rock")
        print("The best music group is The Beatles")
        print("The best lead vocalist is Freddie Mercury")
    else:
        print("The best kind of music is",a)
        print("The best music group is",b)
        print("The best lead vocalist is",c)
    return
def main():
    music, group, singer = input().split(',')
    music_func(music, group, singer)
    music_func() #This is suppose to print the first if-statements 
main()

Answer 1

你可以使用默认参数

def music_func(a="Beatles", b="Classic Rock", c="Freddie"):

现在调用不带参数的函数将默认使用这些选项