所以这是我的代码：
import os
import random
import time
def main():
### Declarations ###
items = []
userItems = []
machineItems = []
totalTies = 0
userWins = 0
cpuWins = 0
### Adding elements ###
items.append("rock")
items.append("paper")
items.append("scissors")
### Function calls ###
replay(items, userItems, machineItems, totalTies, userWins, cpuWins)
os.system('cls')
printResults(userItems, machineItems, totalTies, userWins, cpuWins)
def replay(items, userItems, machineItems, totalTies, userWins, cpuWins):
response = 'yes'
while (response == 'yes'):
print("*Please enter only lower-cased words*")
### It was a tie! ###
## This is also Input Validation for the below loop ##
print("Do you pick: ",
"\n\t1. Rock?",
"\n\t2. Paper?",
"\n\t3. Scissors?")
userChoice = input("Object: ")
machineChoice = random.choice(items)
if (userChoice == machineChoice):
print("Another game is to be played.")
time.sleep(.5)
print("Seting up...")
time.sleep(1)
os.system('cls')
print("Do you pick: ",
"\n\t1. Rock?",
"\n\t2. Paper?",
"\n\t3. Scissors?")
userChoice = input("Object: ")
machineChoice = random.choice(items)
totalTies += 1
userItems.append(userChoice)
machineItems.append(machineChoice)
os.system('cls')
while (userChoice == machineChoice):
print("Another game is to be played.")
time.sleep(.5)
print("Seting up...")
time.sleep(1)
print("Do you pick: ",
"\n\t1. Rock?",
"\n\t2. Paper?",
"\n\t3. Scissors?")
userChoice = input("Object: ")
machineChoice = random.choice(items)
totalTies += 1
userItems.append(userChoice)
machineItems.append(machineChoice)
os.system('cls')
### User picked "rock" ###
elif(userChoice == "rock"):
if(machineChoice == "paper"):
print("You chose: ", userChoice)
time.sleep(.5)
print("The computer chose: ", machineChoice)
time.sleep(.5)
print("And the verdict is...")
time.sleep(1.5)
print("Paper covers rock.")
time.sleep(.5)
print("You lose.")
cpuWins += 1
userItems.append(userChoice)
machineItems.append(machineChoice)
os.system('cls')
elif(machineChoice == "scissors"):
print("You chose: ", userChoice)
time.sleep(.5)
print("The computer chose: ", machineChoice)
time.sleep(.5)
print("And the verdict is...")
time.sleep(1.5)
print("Rock crushes scissors.")
time.sleep(.5)
print("You win!")
userWins += 1
userItems.append(userChoice)
machineItems.append(machineChoice)
os.system('cls')
### User picked "paper" ###
elif(userChoice == "paper"):
if(machineChoice == "scissors"):
print("You chose: ", userChoice)
time.sleep(.5)
print("The computer chose: ", machineChoice)
time.sleep(.5)
print("And the verdict is...")
time.sleep(1.5)
print("Scissors cuts paper.")
time.sleep(.5)
print("You lose.")
cpuWins += 1
userItems.append(userChoice)
machineItems.append(machineChoice)
os.system('cls')
elif(machineChoice == "rock"):
print("You chose: ", userChoice)
time.sleep(.5)
print("The computer chose: ", machineChoice)
time.sleep(.5)
print("And the verdict is...")
time.sleep(1.5)
print("Paper covers rock.")
time.sleep(.5)
print("You win!")
userWins += 1
userItems.append(userChoice)
machineItems.append(machineChoice)
os.system('cls')
### User picked "scissors" ###
elif(userChoice == "scissors"):
if(machineChoice == "rock"):
print("You chose: ", userChoice)
time.sleep(.5)
print("The computer chose: ", machineChoice)
time.sleep(.5)
print("And the verdict is...")
time.sleep(1.5)
print("Rock smashes scissors.")
time.sleep(.5)
print("You lose.")
cpuWins += 1
userItems.append(userChoice)
machineItems.append(machineChoice)
os.system('cls')
elif(machineChoice == "paper"):
print("You chose: ", userChoice)
time.sleep(.5)
print("The computer chose: ", machineChoice)
time.sleep(.5)
print("And the verdict is...")
time.sleep(1.5)
print("Scissors cuts paper.")
time.sleep(.5)
print("You win!")
userWins += 1
userItems.append(userChoice)
machineItems.append(machineChoice)
os.system('cls')
response = input("Replay? ('yes' to continue) ")
os.system('cls')
def printResults(userItems, machineItems, totalTies, userWins, cpuWins):
print("You chose: ", "\n")
for i in userItems:
print("\t", i)
print("The computer chose: ", "\n")
for i in machineItems:
print("\t", i)
print("Total ties: ", totalTies)
print("User wins: ", userWins)
print("Computer wins: ", cpuWins)
gamesPlayed = (totalTies + userWins + cpuWins)
print("Games played: ", gamesPlayed)
input("Press [Enter] to continue...")
main()
这应该是一个Rock_Paper_Scissors程序，如果存在平局则会重新启动，记录userWins，cpuWins和totalTies。当我运行它时，一切正常，除了userWins，cpuWins，totalTies没有收到更新的值，所以当我在程序结束时打印出结果时，为了向用户展示他们是如何做的，它会说userWins，cpuWins，totalTies和gamesPlayed都是0.我不明白，因为这些列表userItems和machineItems，用于向用户显示每方选择的内容，但不是先前声明的变量。有人可以告诉我我做错了什么吗？提前谢谢！
答案 0 :(得分：0)
Python中的列表是可变的。整数不是。因此，您不能通过将其作为函数参数传递来更新整数值。
最小可重现代码：
def f(a_list, an_integer):
a_list.append(3)
an_integer += 1
print a_list, an_integer
l = []
i = 1
f(l, i) # output: [3] 2
f(l, i) # [3, 3] 2
f(l, i) # [3, 3, 3] 2
print l, i # [3, 3, 3] 1
解决方案是从函数返回这些值并显式更新这些整数。
totalTies, userWins, cpuWins = replay(...)
答案 1 :(得分：0)
在Python中将值传递给函数会创建值的副本，因此无法通过修改函数中的值来更新原始函数参数：
def a(mynumber):
mynumber = 10
mynumber = 5
a(mynumber)
print(mynumber) # will print 5
即使对于列表和复杂对象，这也是一样的 - 虽然你可以修改调用对象的方法，这可能会修改它的状态，你不能替换调用者代码中的实际引用。
在您的情况下，一种可能的解决方案是使用全局变量并且不将“共享”变量作为参数传递：
userItems = 0
machineItems = 0
totalTies = 0
userWins = 0
cpuWins = 0
def replay(items):
global userItems, machineItems, totalTies, userWins, cpuWins
...
def printResults():
global userItems, machineItems, totalTies, userWins, cpuWins
...
答案 2 :(得分：0)
感谢您的所有帮助，但我已经明白了。
这是main()和printResults()应该是这样的：
def main():
### Declarations ###
items = []
userItems = []
machineItems = []
totalTies = []
userWins = []
cpuWins = []
### Adding elements ###
items.append("rock")
items.append("paper")
items.append("scissors")
### Function calls ###
replay(items, userItems, machineItems, totalTies, userWins, cpuWins)
os.system('cls')
printResults(userItems, machineItems, totalTies, userWins, cpuWins)
def printResults(userItems, machineItems, totalTies, userWins, cpuWins):
print("You chose: ", "\n")
for i in userItems:
print("\t", i)
print("The computer chose: ", "\n")
for i in machineItems:
print("\t", i)
print("Total ties: ", sum(totalTies))
print("User wins: ", sum(userWins))
print("Computer wins: ", sum(cpuWins))
gamesPlayed = (sum(totalTies) + sum(userWins) + sum(cpuWins))
print("Games played: ", gamesPlayed)
input("Press [Enter] to continue...")
答案 3 :(得分：0)
这里的问题是整数在python中是不可变的。当您递增变量userWins，cpuWins和totalTies的值时，变量的值会在replay函数内更新。另一方面，列表是可变的。因此，如果修改函数内的列表（添加或删除元素），则更改将反映在函数外部。
您可以做两件事：
使函数返回已更改的整数值。
在replay功能
return (totalTies, userWins, cpuWins)
此外，将您调用replay函数的行修改为以下内容：
(totalTies, userWins, cpuWins)=replay((items, userItems, machineItems, totalTies, userWins, cpuWins)
此代码现在应该有效。