python使用map来模拟switch

使用python中的字典来模拟其他语言中的case,switch 语句。
使用函数作为字典的value. 看代码很直观。
该代码出自The Python Master一书.

def labyrinth(position, alive):
    print('You are in a maze of twisty passages, all alike.')
    return position, alive

def dark_forest_road(position, alive):
    print("You are on a road in a dark forest. To"
    " The north you can see a tower.")
    return position, alive

def tall_tower(position, alive):
    print("There is a tall tower here, with no obvious door. "
    "A path leads east.")
    return position, alive

def rabbit_hole(position, alive):
    print("You fall down a rabbit hole into a labyrinth.")
    return (0,0), alive

def lava_pit(position, alive):
    print("You fall into a lava pit.")
    return position, False

def go_north(position):
    i, j = position
    new_position = (i, j + 1)
    return new_position

def go_east(position):
    i, j = position
    new_position = (i + 1, j)
    return new_position

def go_south(position):
    i, j = position
    new_position = (i, j - 1)
    return new_position

def go_west(position):
    i, j = position
    new_position = (i - 1, j)
    return new_position

def look(position):
    return position

def quit(position):
    return None

locations = {
    (0, 0): labyrinth,
    (1, 0): dark_forest_road,
    (1, 1): tall_tower,
    (2, 1): rabbit_hole,
    (1, 2): lava_pit,
    }

actions = {
    'N': go_north,
    'E': go_east,
    'S': go_south,
    'W': go_west,
    'L': look,
    'Q': quit,
    }



def play():

    position = (0, 0)
    alive = True

    while position:

        try:
            location_action = locations[position]
        except KeyError:
            print("There is nothing here.")
        else:
            position, alive = location_action(position, alive)
            if not alive:
                print("You're dead")
                break

        command = input()

        try:
            command_action = actions[command]
        except KeyError:
            print("I don't understand")
        else:
            position = command_action(position)


    else: #nobreak
        print("You have chosen to leave the game")

    print("Game Over")

play()

执行起来结果如下：

root@kali:/usr/local/src/py/project_dirs# ./emulate_switch_3.py 
You are in a maze of twisty passages, all alike.
E
You are on a road in a dark forest. To The north you can see a tower.
N
There is a tall tower here, with no obvious door. A path leads east.
N
You fall into a lava pit.
You're dead
Game Over
root@kali:/usr/local/src/py/project_dirs# ./emulate_switch_3.py 
You are in a maze of twisty passages, all alike.
E
You are on a road in a dark forest. To The north you can see a tower.
N
There is a tall tower here, with no obvious door. A path leads east.
E
You fall down a rabbit hole into a labyrinth.
E
You are on a road in a dark forest. To The north you can see a tower.
N
There is a tall tower here, with no obvious door. A path leads east.
E
You fall down a rabbit hole into a labyrinth.
Q
You have chosen to leave the game
Game Over