Python编写石头剪刀布游戏时rps_choice变量未定义报错如何解决

这是局部变量作用域限制+函数返回值未接收导致的问题：

• 定义在rps_input()内部的rps_choice是函数局部变量，仅在rps_input()的执行范围内有效，外层的Rock_Paper_Scissors函数无法直接访问这个内部变量
• 你虽然在rps_input()里通过return语句返回了rps_choice的值，但调用rps_input()时没有用变量接住返回值，外层函数的作用域里始终没有创建名为rps_choice的变量，运行时自然会触发未定义报错。

只需要修改两处调用rps_input()的代码，接收返回值即可：

1. 首次调用rps_input()时赋值给外层变量：

# 原代码：rps_input()
rps_choice = rps_input()

2. 平局分支下重新调用rps_input()时也要重新赋值：

if rps_choice == rps_random:
    print("You both picked the same. Please try again.")
    # 原代码：rps_input()
    rps_choice = rps_input()

import time
import random

def Rock_Paper_Scissors():
  print("Welcome to the \"Rock, Paper, Scissors\" game!")

  time.sleep(2)

  def rps_input():
    while True:
      rps_choice = input("Say \"Rock\", \"Paper\", or \"Scissors\" to get started: ")

      if rps_choice.upper() == "ROCK":
        print("Great! You chose", rps_choice.upper(), end='')
        print("! The computer picked...")
        return rps_choice.upper()
      if rps_choice.upper() == "PAPER":
        print("Great! You chose", rps_choice.upper(), end='')
        print("! The computer picked...")
        return rps_choice.upper()
      if rps_choice.upper() == "SCISSORS":
        print("Great! You chose", rps_choice.upper(), end='')
        print("! The computer picked...")
        return rps_choice.upper()
      
      else:
        print("Sorry, please say \"Rock\", \"Paper\", or \"Scissors.\"")

        time.sleep(2)

        print("\n")

  # 修复1：接收返回值
  rps_choice = rps_input()

  time.sleep(2)

  rps_list = ["ROCK","PAPER","SCISSORS"]

  rps_random = random.choice(rps_list)
  print(rps_random, end='')
  print("!")

  time.sleep(2)

  if rps_choice == rps_random:
    print("You both picked the same. Please try again.")
    # 修复2：重新接收返回值
    rps_choice = rps_input()
  else:

    if rps_choice == "ROCK":

      if rps_random == "PAPER":
        print("The computer's paper beats your rock.")

        time.sleep(2)

        print("You LOSE.")
      if rps_random == "SCISSORS":
        print("Your rock beats the computer's scissors!")

        time.sleep(2)

        print("You WIN.")
    if rps_choice == "PAPER":

      if rps_random == "ROCK":
        print("Your paper beats the computer's rock!")

        time.sleep(2)

        print("You WIN.")
      if rps_random == "SCISSORS":
        print("The computer's scissors beats your paper.")

        time.sleep(2)

        print("You LOSE.")
      
    else:
      
      if rps_random == "ROCK":
        print("The computer's rock beats your scissors.")

        time.sleep(2)

        print("You LOSE.")
      if rps_random == "PAPER":
        print("Your scissors beat the computer's paper.")

        time.sleep(2)

        print("You WIN.")

  time.sleep(2)

  def RPS_Reset_Quit():
    rq = input("Restart or quit? (R/Q): ")
    if rq.lower() == "r":
      print("\n")
      Rock_Paper_Scissors()
    if rq.lower() == "q":
      print("Quiting...")

      time.sleep(2)

      quit()
    else:
      print("Sorry, please say either R or Q.")

      time.sleep(2)

      RPS_Reset_Quit()
  RPS_Reset_Quit()

Rock_Paper_Scissors()

当前修复后的代码仍存在一个小逻辑缺陷：平局时用户重新选择后，电脑不会重新生成随机选择，仍会使用上一轮的结果。如果要优化可以将「生成电脑随机值+胜负判断」的逻辑也放到循环里，平局时就重新执行完整的选择流程。

内容的提问来源于stack exchange，提问作者Mr. Unknownymous