Python中布尔值控制的while循环无条件重复运行问题排查

错误原因 #

• 核心问题是混淆了Python中的赋值运算符=和相等比较运算符==。你代码里给anotherNum赋值的两行都写成了==，这行代码只会判断anotherNum是否等于后面的值，不会真正修改它的数值。只要你初始化时anotherNum设为True，循环条件就永远成立，自然不会进入后续的游戏结束逻辑。
• 其次你对用户输入的判断只匹配了大写Y，输入小写y、n或者大写N时都会进入else分支，哪怕你写了break语句，如果因为赋值逻辑失效、缩进错误没触发break，循环就会一直执行。
• 从你给出的运行输出看total没有累加，每次都是新生成的点数数值，说明你大概率把total的初始化代码写在了while循环内部，每次循环都会把total重置为初始值，看起来就像跳过了total = total + playerNum语句。

修复后代码 #

import random
# 变量初始化必须放在循环外部
total = 0
pcNum = random.randint(1, 13)
name = "玩家"
anotherNum = True

while anotherNum:
    playerNum = random.randint(1,10)
    total += playerNum
    print("")
    print("Your number is ", str(playerNum) + ".")
    print("You have " + str(total) + " in total.")
    print("")
    # 输入转为大写，兼容大小写输入
    again = input("Roll another number? <Y or N> ").strip().upper()
    print("")
    if again == "Y":
        anotherNum = True
    else:
        anotherNum = False

# game finished now
print("Computer got", pcNum)
print("You got", total)
# 判定胜负的逻辑不需要写while循环，因为只会执行一次，直接写判断即可
if (total <= 13) and (total > pcNum): 
    print("You,", name, "have won!")
elif (pcNum <= 13) and (pcNum > total):
    print("The computer has bested you,", name + "!")
else:
    if (total == pcNum) and (total <= 13):
        print("Draw...")
    elif (pcNum > 13) and (total <= 13):
        print("You,", name + " have won!")
    else:
        print("Both of you have lost. Wow...")

内容的提问来源于stack exchange，提问作者fleur333