石头剪刀布游戏Bug：合法输入仍触发‘Invalid input’提示

你的代码中无效输入判断的逻辑条件错误，导致无论输入rock、paper还是scissors，都会触发"Invalid input"的打印。

问题原因 #

这段判断条件：

if player_choice != "rock" or player_choice != "paper" or player_choice != "scissors":
    print("Invalid input")

逻辑上永远为真。因为当你输入rock时，player_choice != "paper"和player_choice != "scissors"都是真，or只要有一个条件为真整个表达式就为真；同理输入paper或scissors时，另外两个不等于的条件也会成立，所以每次都会执行打印。

解决方案 #

你需要把判断逻辑改成同时不满足三个合法值时才判定为无效输入，有两种写法：

1. 使用and替代or：

if player_choice != "rock" and player_choice != "paper" and player_choice != "scissors":
    print("Invalid input")

2. 更简洁的写法：用not in检查输入是否不在合法列表中：

if player_choice not in ["rock", "paper", "scissors"]:
    print("Invalid input")

修正后的完整代码 #

import random

round_count = int(input("How many rounds would you like to play? "))
score = 0

for i in range(int(round_count)):
    computer_choice = random.choice(["rock", "paper", "scissors"])
    player_choice = input("Rock, Paper, Scissors? ").lower()

    if computer_choice == player_choice:
        print("Tie")
        # add_round_for_tie = input("Would you like to add a round because of the tie?")
        # if add_round_for_tie.lower() == "yes":
        # round_count += 1

    else:
        if computer_choice == "paper" and player_choice == "scissors":
            print("Scissors beats paper. You win!")
            score += 1
        if computer_choice == "scissors" and player_choice == "paper":
            print("Scissors beats paper. You lost.")
        if computer_choice == "rock" and player_choice == "scissors":
            print("Rock beats scissors. You lost.")
        if computer_choice == "scissors" and player_choice == "rock":
            print("Rock beats scissors. You win!")
            score += 1
        if computer_choice == "paper" and player_choice == "rock":
            print("Paper beats rock. You lost.")
        if computer_choice == "rock" and player_choice == "paper":
            print("Paper beats rock. You win!")
            score += 1

    # 修正后的无效输入判断
    if player_choice not in ["rock", "paper", "scissors"]:
        print("Invalid input")

print(f"Your score is {score}/{round_count}")

内容的提问来源于stack exchange，提问作者oiecodes