为什么我的 python 函数被调用了两次？

Question

我对 python 还很陌生，每当我运行我的脚本时，前两个函数 humanPlay() 和 computerPlay() 都会被调用两次。我不想要这个。

我注意到，当我在 setRules() 函数中注释掉 draw 变量时，程序可以正常运行。我不确定为什么 f"{computerPlay()}" 和 f"{humanPlay()}" 不打印返回值。

我还验证了py文件没有命名为Random，以防止模块自行导入。

import random


Player = "Player"
Computer = "Computer"
options = ["ROCK","PAPER","SCISSORS"]

def main():
    def humanPlay():
        response = input("Make a selection between Rock, Paper, Scissors: ", )
        response.upper()

        if response.upper() in options:
            print(response.upper())
            return response.upper()
        else:
            print(f"{response.upper()}, is not a valid selection")
            return humanPlay()

    def computerPlay():
         print(random.choice(options))
         return random.choice(options)

    def setRules():
        rockWin = "You Win! ROCK beats SCISSORS "
        paperWin = "You Win! PAPER beats ROCK "
        scissorsWin = "You Win! SCISSORS beats PAPER "
        draw = print("It's a Draw!, computer selected", f"{computerPlay()}", "and you selected", f"{humanPlay()}")
        #loser = print(f"You Lose! {humanPlay()}", f"can't beat {computerPlay()}")


    humanPlay()
    computerPlay()
    setRules()

main()

理想情况下，draw 变量应该类似于以下内容：

It's a Draw!, computer selected ROCK and you selected ROCK

注意：我仍然需要为程序编写逻辑才能知道石头、纸和剪刀之间的区别。

现在我只想返回正确的值，而不是整个函数。

Answer 1

• 如 cmets 中所述，函数在 main 内被调用两次
  • 一次在main的底部
  • 曾经在setRules
• 函数不应驻留在main
• 应从main 调用函数，并将值returned 存储为变量以在setRules 中使用
• 逻辑未设置为在rock、paper 或scissor 之间确定获胜者
• 有效的scope ofPlayer、Computer和options是全局的。

def humanPlay() -> str:
    response = input("Make a selection between Rock, Paper, Scissors: ", )
    response = response.upper()

    if response in options:
        print(response)
        return response
    else:
        print(f"{response}, is not a valid selection")
        return humanPlay()

def computerPlay() -> str:
    comp_choice = random.choice(options)
    print(comp_choice)
    return comp_choice

def setRules(comp_choice: str, human_choice: str):
    rockWin = "You Win! ROCK beats SCISSORS "
    paperWin = "You Win! PAPER beats ROCK "
    scissorsWin = "You Win! SCISSORS beats PAPER "
    draw = print("It's a Draw!, computer selected", f"{comp_choice}", "and you selected", f"{human_choice}")
    #loser = print(f"You Lose! {human_choice}", f"can't beat {comp_choice}")

Player = "Player"
Computer = "Computer"
options = ["ROCK","PAPER","SCISSORS"]

def main():

    h_choice = humanPlay()
    c_choice = computerPlay()

    setRules(c_choice, h_choice)

main()

Answer 2

问题在于您对 f 字符串插值和一般函数调用的解释。

当您拥有some_func() 时，这将调用该函数（即其中的代码将被执行）。

f-string 插值的工作原理是它里面的任何东西都会被执行，并且它的结果将被转换为字符串。

因此，要修复（这方面）您的代码，您应该将humanPlay() 和computerPlay() 的结果收集到某个变量中，例如human_move = humanPlay() 然后将该值传递给setRules()（同时确保setRules() 实际接受该值）。

Answer 3

您看到humanPlay() 和computerPlay() 被调用两次的原因是因为您是！
当您在 setRules 中打印它们时：
draw = print("It's a Draw!, computer selected", f"{computerPlay()}", "and you selected", f"{humanPlay()}") 您没有得到以前的结果，而是再次调用它们。

我会将 humanPlay 和 computerPlay 的返回值分配给一些变量并将其传递给 setRules。

即

import random


Player = "Player"
Computer = "Computer"
options = ["ROCK","PAPER","SCISSORS"]

def main():
    def humanPlay():
        response = input("Make a selection between Rock, Paper, Scissors: ", )
        response.upper()

        if response.upper() in options:
            print(response.upper())
            return response.upper()
        else:
            print(f"{response.upper()}, is not a valid selection")
            return humanPlay()

    def computerPlay():
         choice = random.choice(options)
         return choice

    def setRules(humanResult, computerResult):
        rockWin = "You Win! ROCK beats SCISSORS "
        paperWin = "You Win! PAPER beats ROCK "
        scissorsWin = "You Win! SCISSORS beats PAPER "
        print("It's a Draw!, computer selected", f"{computerResult}", "and you selected", f"{humanResult}")
        #loser = print(f"You Lose! {humanResult}", f"can't beat {computerResult}")


    hResult = humanPlay()
    cResult = computerPlay()
    setRules(hResult, cResult)

main()