Python中如何将一个函数内定义的变量传递给另一个独立函数

背景 #

我确信这个问题在其他地方已有提问，但我目前找到的相关主题都比我现在做的内容更复杂，只会让我更困惑。我是Python入门课程的学生，正在完成一个“彩票号码”作业，基础要求是随机生成7位彩票号码并打印输出。
基础要求我已经掌握，但我不想只按字面要求完成，想做得更实用：也就是让用户自定义需要生成的号码数量、可选号码的取值范围，再由程序生成符合用户设定标准的随机号码。
我的讲师要求所有逻辑都要在函数内实现，所以我计划按如下结构开发：

实现思路 #

• main() 函数：作为程序入口调度所有逻辑
• get_info() 函数：收集用户输入的参数，包括号码数量MaxDigits、取值范围最小值MinChoice、取值范围最大值MaxChoice
• lottery_pick() 函数：接收上述参数，完成彩票号码生成逻辑

问题描述 #

目前代码可以运行，但我只能把lottery_pick() 函数定义在get_info() 函数内部才能调用执行。我想知道有没有方法可以将两个函数独立定义，只把get_info() 中生成的变量传递给lottery_pick() 即可。

原始代码 #

import random
# Define the main function
def main():
    get_info()
    exit_prompt()
def get_info():
    # Set Variables to 0
    MaxDigits = 0
    # Let the user know what we are doing
    print("Let's choose your lottery numbers!")
    print("First, How many numbers do you need for this lottery?")
    # Request the user input the number of lottery numbers we need
    while True:
        try:
            MaxDigits = int(input('Please enter how many numbers you need to choose: '))
            if MaxDigits > 0:
                break;
            else:
                print('Please enter an integer for how many numbers are being drawn. ')
        except:
            continue
    print('Next, we need to know the smallest and largest numbers allowed to choose from')
    # Request user input smallest number in range of numbers to pick from.
    while True:
        try:
            MinChoice = int(input('Please enter the lowest number you are allowed to choose from: '))
            if MinChoice >= 0:
                break;
            else: print ('Please enter an integer, 0 or greater for the smallest number to pick from.')
        except:
            continue
    # Request user input largest number in range of numbers to pick from.
    while True:
        try:
            MaxChoice = int(input('Please enter the largest number you are allowed to choose from: '))
            if MaxChoice >= 0:
                break;
            else: print ('Please enter an integer, 0 or greater for the greatest number to pick from.')
        except:
            continue
    # Define the function to actually assemble the lottery number
    def lottery_pick(lot_digits, lot_min, lot_max):
        numbers = [0] * lot_digits
        for index in range(lot_digits):
            numbers[index] = random.randint (lot_min, lot_max)
        print('Here are your lottery numbers!:')
        print(numbers)
    # Execute the function - I've not yet figured out how to pass the variables from the get_info
    # function to the lottery_pick function without lottery_pick being inside of get_info.
    lottery_pick(MaxDigits, MinChoice, MaxChoice)
def exit_prompt():
    while True:
        try:
# use lower method to convert all strings input to lower-case. This method
# allows user to input their answer in any case or combination of cases.
            ExitPrompt = str.lower(input('Would you like to generate another lottery number? Please enter "yes" or "no" '))
            if ExitPrompt == 'yes':
                 main()
            elif ExitPrompt =='no':
                print('Goodbye!')
                exit()
# If an answer other than yes or no is input, prompt the user again to choose to re-run or to exit
# until an acceptable answer is provided.
            else:
                print('Please enter "yes" to generate another lottery number, or "no" to exit. ')
        except:
            continue
main()

修改方案 #

核心调整点 #

1. 将lottery_pick()函数从get_info()内部移出，作为独立的顶层函数定义
2. 改造get_info()，收集完三个参数后直接返回这三个值
3. 在main()函数中接收get_info()的返回值，再传递给lottery_pick()执行

修改后完整代码（已汉化交互提示） #

import random
# 独立定义的彩票生成函数
def lottery_pick(lot_digits, lot_min, lot_max):
    numbers = [random.randint(lot_min, lot_max) for _ in range(lot_digits)]
    print('您的彩票号码如下：')
    print(numbers)
def main():
    # 接收get_info返回的三个参数
    max_digits, min_choice, max_choice = get_info()
    # 传递参数给独立的lottery_pick函数
    lottery_pick(max_digits, min_choice, max_choice)
    exit_prompt()
def get_info():
    max_digits = 0
    print("欢迎使用彩票号码生成器！")
    print("第一步，请输入需要生成的号码位数：")
    while True:
        try:
            max_digits = int(input('请输入需要生成的号码个数：'))
            if max_digits > 0:
                break
            else:
                print('请输入大于0的正整数')
        except:
            print('输入无效，请输入正整数')
            continue
    print('第二步，请输入可选号码的取值范围')
    while True:
        try:
            min_choice = int(input('请输入取值范围的最小值：'))
            if min_choice >= 0:
                break
            else: 
                print('请输入大于等于0的整数作为最小值')
        except:
            print('输入无效，请输入整数')
            continue
    while True:
        try:
            max_choice = int(input('请输入取值范围的最大值：'))
            if max_choice >= 0 and max_choice > min_choice:
                break
            elif max_choice <= min_choice:
                print('最大值必须大于你输入的最小值，请重新输入')
            else: 
                print('请输入大于等于0的整数作为最大值')
        except:
            print('输入无效，请输入整数')
            continue
    # 收集完所有参数后直接返回
    return max_digits, min_choice, max_choice
def exit_prompt():
    while True:
        try:
            exit_prompt_val = input('是否需要重新生成号码？请输入“是”或“否”：').lower()
            if exit_prompt_val == '是':
                 main()
            elif exit_prompt_val == '否':
                print('再见！')
                exit()
            else:
                print('输入无效，请输入“是”重新生成，或输入“否”退出程序')
        except:
            continue
if __name__ == "__main__":
    main()

补充说明 #

修改后额外增加了最大值必须大于最小值的校验，避免用户输入无效的取值范围。同时将原来的列表赋值写法改成了更简洁的列表推导式写法，功能完全一致，更符合Python的常用写法。 #

内容的提问来源于stack exchange，提问作者Jeremy