Detailed explanation of Python three-level menu examples

The editor below will bring you an example of a Python three-level menu. The editor thinks it’s pretty good, so I’ll share it with you now and give it as a reference. Let’s follow the editor and take a look.

Requirements:

Print the provincial, city and county three-level menu

You can return to the previous level

You can exit the program at any time

Version 1

# _author : Ahern Li
# @_date : 2017/9/12

menu = {
  '浙江省':{
    '杭州市':{
      '余杭区':{'中泰':{},'临平':{}},
      '西湖区':{'西湖':{},'留下':{}}
      },
    '温州市':{
      '苍南县':{'灵溪':{},'龙港':{}},
      '瑞安县':{'安阳':{},'锦湖':{}}
      }
    },
  '广东省':{
    '广州市':{
      '越秀区':{'人民路':{},'北京路':{}},
      '荔湾区':{'沙面':{},'龙津':{}}
      },
    '珠海市':{
      '香洲区':{'拱北':{},'吉大':{}},
      '金湾区':{'红旗镇':{},'平沙镇':{}}
      }
    }
  }

# 返回标记
q_flag = True
# 退出标记
Q_flag = True
# 返回，退出标记出现False退出循环
while q_flag and Q_flag:
  # 遍历打印省份
  for i in menu:
    print(i)
  province = input('请输入要查找的省份(Q,退出):').strip()
  if province in menu:
    while q_flag and Q_flag:
      for i in menu[province]:
        print(i)
      city = input('请输入要查找的市(q,返回 或 Q,退出):').strip()
      if city in menu[province]:
        while q_flag and Q_flag:
          for i in menu[province][city]:
            print(i)
          county = input('请输入要查找的区或县(q,返回 或 Q,退出):').strip()
          if county in menu[province][city]:
            while q_flag and Q_flag:
              for i in menu[province][city][county]:
                print(i)
              # 提示最后一页，输入格式
              choice = input('最后一页! q,返回 或 Q,退出:').strip()
              if choice == 'q':
                # 配合 else: q_flag = True 退出该层循环，返回上层循环
                q_flag = False
              elif choice == 'Q':
                # 退出大循环
                Q_flag = False
              else:
                # 提示输入不合法
                print('输入错误!')
            # 改回 q_flag 的值，实现只退出一层循环
            else:
              q_flag = True
          elif county == 'q':
            q_flag = False
          elif county == 'Q':
            Q_flag = False
          else:
            print('输入错误!')
        else:
          q_flag = True
      elif city == 'q':
        q_flag = False
      elif city == 'Q':
        Q_flag = False
      else:
        print('输入错误!')
    else:
      q_flag = True
  elif province == 'Q':
    Q_flag = False
  else:
    print('输入错误!')

Version 2

# _author : Ahern Li
# @_date : 2017/9/12

menu = {
  '浙江省':{
    '杭州市':{
      '余杭区':{'中泰':{},'临平':{}},
      '西湖区':{'西湖':{},'留下':{}}
      },
    '温州市':{
      '苍南县':{'灵溪':{},'龙港':{}},
      '瑞安县':{'安阳':{},'锦湖':{}}
      }
    },
  '广东省':{
    '广州市':{
      '越秀区':{'人民路':{},'北京路':{}},
      '荔湾区':{'沙面':{},'龙津':{}}
      },
    '珠海市':{
      '香洲区':{'拱北':{},'吉大':{}},
      '金湾区':{'红旗镇':{},'平沙镇':{}}
      }
    }
  }

current_layer = menu  # 实现动态循环
parent_layer = []  # 保留所有父层，最后一个元素永远为父层

while True:
  print() # 仅为了打印美观
  for i in current_layer:   # 遍历打印地址
    print(i)
  choice = input('请在下方输入查询地址\n>>>:').strip()
  if choice in current_layer:
    if current_layer[choice]:  # 判断是否为末层
      parent_layer.append(current_layer) # 进入子层前，添加当前层作为父层
      current_layer = current_layer[choice]  # 修改子层
    else:
      print('当前是最后一页')
  elif choice == '':
    continue
  elif choice == 'q':   # 返回上层
    if parent_layer:  # 判断 parent_layer 是否为空
      current_layer = parent_layer.pop() # 取出当前层父层
  # 退出循环
  elif choice == 'Q':
    break
  else:
    print('输入错误!')

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