聲明變量運行而不運行

Question

def user(choose):
    if (choose == "1"):
        play = game()
    elif (choose == "2"):
        return stats(play)
    else:
        return quit()

我想從game（）函數中獲取值並在stats（）中使用它，但是我收到一條錯誤消息，說未定義游戲。 如何聲明game（）並在另一個函數中使用它？

Answer 1

您可以“推遲”執行func1 ：

def func1():
    return 'abc'

def something_else(callable):
    callable()

def main():
    hello = None

    def f():
        """set result of func1 to variable hello"""
        nonlocal hello
        hello = func1()

    # over here func1 is not executed yet, hello have not got its value
    # you could pass function f to some other code and when it is executed, 
    # it would set result for hello 
    print(str(hello))  # would print "None"
    call_something_else(f)
    print(str(hello))  # would print "abc"

main()

問題改變之后...

現在，您的本地變量play超出了統計范圍。 此外，看起來您希望該函數將被調用兩次。 您需要將play內容保存在全局內容中

play = None  # let's set it to some default value
def user(choose):
    global play  # let python know, that it is not local variable

    if choose == "1":  # no need for extra brackets
        play = game()

    if choose == "2" and play:  # double check that play is set
        return stats(play)

    return quit()