Python: match case

 

1. def alarm(item: list):
       match item:
           case [time, action]:
               print(f'{time} {action}')
           case [time, *actions]:
               for action in actions:
                   print(f'^^ {time} {action}')
   
   
   alarm(['afternoon', 'work'])
   
   alarm(['morning', 1, 5, 6])

   
   
   

2. def alarm(item: list):
       match item:
           case [('morning' | 'afternoon' | 'evening') as time, action]:
               print(f'Good {time} {action}')
           case _:
               print('invalid')
   
   
   alarm(['qwer'])
   alarm(['evening', 'work'])

    

3. def alarm(item: list):
       match item:
           case ['evening', action]:
               print(f'You almost finished the day! Now {action}')
           case [time, action]:
               print(f'Good {time} It is time to {action}')
           case _:
               print('default')
   
   
   alarm(['qwer'])
   alarm(['evening', 'work'])
   alarm(['morning', 55])

   def alarm(item: list):
       match item:
           case ['evening', action] if action not in ['work', 'study']:
               print(f'You almost finished the day! Now {action}')
           case [time, action]:
               print(f'Good {time} It is time to {action}')
           case _:
               print('default')
   
   
   alarm(['qwer'])
   alarm(['evening', 'work'])
   alarm(['evening', 'qwer'])
   alarm(['morning', 55])

    

4. class Direction:
       def __init__(self, horizontal=None, vertical=None):
           self.horizontal = horizontal
           self.vertical = vertical
   
   
   def location(direction: Direction):
       match direction:
           case Direction(horizontal='east', vertical='north'):
               print(direction, 11)
           case Direction(horizontal='west', vertical='south'):
               print(direction, 22)
           case Direction(horizontal=None, vertical=y):
               print(direction, 33, y)
           case Direction(horizontal=x, vertical=None):
               print(direction, 44, x)
           case Direction(horizontal=x, vertical=y):
               print(direction, 55, x, y)
           case _:
               print('invalid')
   
   
   location(Direction('east', 'north'))
   location(Direction('west', 'south'))
   location(Direction(None, 'qwer'))
   location(Direction('rtyu', None))
   location(Direction('zxc', 'uiop'))
   location(Direction())
   location(55)

    

5. def status(status: int):
       match status:
           case 400:
               return 'Bad Request'
           case 401 | 403:
               return 'Authentication Error'
           case _:
               return 'Others'

    

 

match依然没有产生新的作用域, match先进行case后面的deconstruct,取得变量,而后进行if判断

 

 

match会进行短路, 注意time也是UnboundLocalError