python_多级菜单_纯循环与分支

源代码：

#!/usr/bin/python3

__author__ = 'beimenchuixue'
__blog__ = 'http://www.cnblogs.com/2bjiujiu/'

def menu(message):
    print('按q返回上一层')
    print('按e退出')
    ec = 'q'                                    # 返回上一级
    ex = 'e'
    for i in message:                              # 打印一级菜单
        print(i)
    while True:                                 # 进入一级菜单选择
        choice1 = input('请输入1>>>：')
        if choice1 in message:                     # 判断是否在字典中
            for i1 in message[choice1]:
                print(i1)                       # 打印值

            while True:
                choice2 = input('请输入2>>>：')  # 进入二级菜单选择
                if choice2 in message[choice1]:
                    for i2 in message[choice1][choice2]:
                        print(i2)

                    while True:
                        choice3 = input('请输入3>>>：')     # 进入三级菜单选择
                        if choice3 in message[choice1][choice2]:
                            for i3 in message[choice1][choice2][choice3]:
                                print(i3)

                        elif choice3 == ec:                 # 返回判断
                            for i2 in message[choice1]:
                                print(i2)                   # 打印上一级菜单
                            break

                        elif choice3 == ex:                 # 退出判断
                             exit('退出中……ing')
                        else:
                            print('输入错误，请重新输入，么么哒')

                elif choice2 == ec:                         # 返回判断，并打印上一级菜单
                    for i1 in message:
                        print(i1)
                    break
                elif choice2 == ex:                         # 退出判断
                    exit('退出中……ing')
                else:
                    print('输入错误，请重新输入，么么哒')

        elif choice1 == ec:                                 # 返回判断
            print('已经最顶级菜单，完全退出请输入 e ')
            continue
        elif choice1 == ex:                                 # 退出判断
            exit('退出中……ing')
        else:
            print('输入错误，请重新输入，么么哒')

if __name__ == '__main__':
    message = {'湖南':
                {'衡阳':
                     {'珠晖区': '湖南工学院'},
                 '湘潭':
                     {'晖晖': '啦啦'}},
            '北京':
                {'朝阳':
                     {"德玛：北京大学"}}}
    menu(message)

坑点：
        1.纯分支与循坏，重复代码
        2.多级字典的访问几级就需要几个[]中括号

用面向过程，函数方式做，返回上一级菜单未做，可做一个参考，有更好思路再更新

#!/usr/bin/python3

def menu_to(message):
    '''打印菜单'''
    try:
        message.endswith('end')
    except:
        for i in message:
            print(i)
    else:
        print(message.replace('end', ''))

def get_message_key(message_info):
    '''获得每层字典的单边值'''
    try:
        keys = []
        for i in message_info:
            message_info[i]
            keys.append(i)
        return keys
    except:
        return message_info + 'end'

def menu_go(message_info):
    '''进入主菜单'''
    while True:
        try:
            judgment(message_info)
        except Exception as e:
            print(e)

def judgment(message_info):
    '''循环菜单'''
    keys = get_message_key(message_info)
    while True:
        menu_to(keys)

        choice = input('请输入>>>:')
        if choice == ec:
            print('暂时未实现')
            return judgment(message_info)
        elif choice == ex:
            exit('退出程序')

        if type(keys) == type('str') and keys.endswith('end'):
            print('菜单到底了')
            continue
        else:

            if choice in keys:
                message_info = message_info[choice]
                return judgment(message_info)
            else:
                print('输入错误,请重新输入')

if __name__ == '__main__':
    info_message = {'湖南':
                        {'衡阳':
                             {'珠晖区': '湖南工学院'},
                         '湘潭':
                             {'晖晖': '啦啦'}},
                    '北京':
                        {'朝阳':
                             {"德玛": "北京大学"}}}
    ec = 'q'  # 返回上一级
    ex = 'e'  # 退出程序
    menu_go(info_message)