函数调用函数

Question

这段代码的问题在于，如果您首先输入的不是"bob"，那么当您最终输入"bob"时，main函数将输出None。请运行此代码以充分了解我遇到的问题，并为我提供一些答案。

def main(name):
    print name

def x():
    name = raw_input()
    if name == "bob":
        return name
    else:
        print "error"
        x()

main(x())

Answer 1

这里不要使用递归。一个简单的while循环就足够了。

def get_name_must_be_bob():
    while True:
        name = raw_input("Enter name: ")
        if name.lower() == "bob":   # "Bob", "BOB" also work...
            return name

        # `else` is not necessary, because the body of the `if` ended in `return`
        # (we can only get here if name is not Bob)

        print "Are you sure you're not Bob? Try again."

def main():
    name = get_name_must_be_bob()
    print "Hello, " + name


if __name__ == '__main__':
    main()

Answer 2

在"error“的情况下，您不返回值。将x()更改为return x()