为什么我在 function 中的全局值在打印时返回错误？

Question

def name():
    global x
    x = "Hello"
    print(x + " Guys!")

print(x)
print(name())

the output is

NameError: name 'x' is not defined

Why is this happening? This is weird because I placed the (global) function.

Answer 1

The first time print(x) is called outside the function, the function not having been run yet, x is not defined. Once you run name(), then you can print(x) whenever you like.