Question

我在Python中有一个问题，我想做一个while循环，并要求玩家输入骰子的数量和进行随机骰子滚动的边数。在第二个循环和任何其他循环我想问他们是否愿意继续。如果他们输入＆＃39; n＆＃39;或者没有＆＃39;程序退出。

我能够使用全局变量来处理这个逻辑，并在第一次调用它之后在我的函数中更改该变量，这样第二次会询问用户是否要继续，但是根据我的理解使用全局变量像这样的变量不是一种非常类似Python的方式。我想改进这个。

以下代码有效，但永远不会提示用户退出。我知道这是因为它们变量在while循环开始时仍然设置为True，但我不知道如何设置标志而不诉诸全局变量。

如何在本地（非全局）设置True / False变量并使用它来控制程序中的流程？

import sys
import random

def get_user_input(first_loop):
    if not first_loop:
        another_time = input("Would you like to roll another time?")
        if another_time.lower() in ['n', 'no']:
            sys.exit()
    # This allows the code above to output on additional loops.
    first_loop = False
    return first_loop

while True:
    # How do I not reset this back to True each time the program loops?
    first_loop = True

    get_user_input(first_loop)

    number_of_dice = int(input("Enter the number of dice you would like to roll: "))
    number_of_sides = int(input("Enter the number of sides for the dice: "))

    # create the dice_total list so each time we create a roll in the loop, 
    # it can be added to a list and the total calculated
    dice_total = []

    for die in range(number_of_dice):
        random_roll = random.randrange(1, number_of_sides)
        print("You rolled: ", random_roll)
        dice_total.append(random_roll)

    dice_total = sum(dice_total)
    print("The total of the dice rolled is: ", dice_total)

Answer 1

你非常接近。

# move this outside the loop
first_loop = True

while True:
    if not first_loop:
        get_user_input()
    first_loop = False

无需在first_loop函数本身中使用get_user_input：

def get_user_input():
    another_time = input("Would you like to roll another time?")
    if another_time.lower() in ['n', 'no']:
        sys.exit()

最好返回True / False并相应地采取行动，而不是在函数中使用sys.exit（为您提供更多控制权）：

def get_user_input():
    another_time = input("Would you like to roll another time?")
    return not another_time.lower() in ['n', 'no']

然后你可以这样做：

while True:
    if not first_loop:
        if not get_user_input():
            # break out of the loop
            break

Answer 2

您可以将变量放在list中。这将允许您在get_user_input()函数中更改其值，并避免使其成为全局变量。

import sys
import random

def get_user_input(first_loop):
    if not first_loop[0]:  # access value in the list
        another_time = input("Would you like to roll another time?")
        if another_time.lower() in ['n', 'no']:
            sys.exit()
    # This allows the code above to output on additional loops.
    first_loop[0] = False
    return first_loop[0]  # access value in the list

while True:
    # How do I not reset this back to True each time the program loops?
    first_loop = [True]  # change to a list

    get_user_input(first_loop)

    number_of_dice = int(input("Enter the number of dice you would like to roll: "))
    number_of_sides = int(input("Enter the number of sides for the dice: "))

    # create the dice_total list so each time we create a roll in the loop,
    # it can be added to a list and the total calculated
    dice_total = []

    for die in range(number_of_dice):
        random_roll = random.randrange(1, number_of_sides)
        print("You rolled: ", random_roll)
        dice_total.append(random_roll)

    dice_total = sum(dice_total)
    print("The total of the dice rolled is: ", dice_total)

设置本地bool来控制流

2 个答案: