Function name not defined

问题

I have a pice of code which looks like this

if __name__ == "__main__":
    main()


def main():
    print("hello")

However, when I try to run this code I get the error

NameError: name 'main' is not defined

Have I not defined the name in the first line of the function "def main()"?

回答1:

You should define main before call it

def main():
    print("hello")

if __name__ == "__main__":
    main()

回答2:

Have I not defined the name in the first line of the function "def main()"?

Yes, but Python hasn't executed that definition yet. Put the function definition before the call.

来源：https://stackoverflow.com/questions/23023246/function-name-not-defined