Python实现2048小游戏
https://www.shiyanlou.com/courses/368/learning/
知识点
- Python基本知识
- 状态机的概念
导入相关包：
import curses
from random import randrange, choice
from collections import defaultdict主逻辑
1.用户行为
所有的有效输入都可以转换为"上，下，左，右，游戏重置，退出"这六种行为，用 actions 表示
actions = ['Up', 'Left', 'Down', 'Right', 'Restart', 'Exit']有效输入键是最常见的 W（上），A（左），S（下），D（右），R（重置），Q（退出），这里要考虑到大写键开启的情况，获得有效键值列表：
letter_codes = [ord(ch) for ch in 'WASDRQwasdrq']将输入与行为进行关联：
actions_dict = dict(zip(letter_codes, actions * 2))
2.状态机
处理游戏主逻辑的时候我们会用到一种十分常用的技术：状态机，或者更准确的说是有限状态机（FSM）
你会发现 2048 游戏很容易就能分解成几种状态的转换。
state 存储当前状态， state_actions 这个词典变量作为状态转换的规则，它的 key 是状态，value 是返回下一个状态的函数：
- Init: init()
- Game
- Game: game()
- Game
- Win
- GameOver
- Exit
- Win: lambda: not_game('Win')
- Init
- Exit
- Gameover: lambda: not_game('Gameover')
- Init
- Exit
- Exit: 退出循环
状态机会不断循环，直到达到 Exit 终结状态结束程序。
个人对状态机的思路：
先初始化，游戏开始，赢，输，或者直接退出，或者初始化，赢了，则可退出，可初始化重新开始，输了，也可直接退出，或者初始化重来
def main(stdscr):
def init():
#重置游戏棋盘
return 'Game'
def not_game(state):
#画出 GameOver 或者 Win 的界面
#读取用户输入得到action，判断是重启游戏还是结束游戏
responses = defaultdict(lambda: state) ＃默认是当前状态，没有行为就会一直在当前界面循环
responses['Restart'], responses['Exit'] = 'Init', 'Exit' #对应不同的行为转换到不同的状态
return responses[action]
def game():
#画出当前棋盘状态
#读取用户输入得到action
if action == 'Restart':
return 'Init'
if action == 'Exit':
return 'Exit'
#if 成功移动了一步:
if 游戏胜利了:
return 'Win'
if 游戏失败了:
return 'Gameover'
return 'Game'
state_actions = {
'Init': init,
'Win': lambda: not_game('Win'),
'Gameover': lambda: not_game('Gameover'),
'Game': game
}
state = 'Init'
#状态机开始循环
while state != 'Exit':
state = state_actions[state]()
用户输入处理
阻塞＋循环，直到获得用户有效输入才返回对应行为：
def get_user_action(keyboard):
char = "N"
while char not in actions_dict:
char = keyboard.getch()
return actions_dict[char]
矩阵转置与矩阵逆转
加入这两个操作可以大大节省我们的代码量，减少重复劳动，看到后面就知道了。
矩阵转置：
def transpose(field):
return [list(row) for row in zip(*field)]
矩阵逆转（不是逆矩阵）：
def invert(field):
return [row[::-1] for row in field]
创建棋盘
初始化棋盘的参数，可以指定棋盘的高和宽以及游戏胜利条件，默认是最经典的 4x4～2048。
class GameField(object):
def __init__(self, height=4, width=4, win=2048):
self.height = height #高
self.width = width #宽
self.win_value = 2048 #过关分数
self.score = 0 #当前分数
self.highscore = 0 #最高分
self.reset() #棋盘重置
棋盘操作
1.随机生成一个 2 或者 4
def spawn(self):
new_element = 4 if randrange(100) > 89 else 2
(i,j) = choice([(i,j) for i in range(self.width) for j in range(self.height) if self.field[i][j] == 0])
self.field[i][j] = new_element
2.重置棋盘
def reset(self):
if self.score > self.highscore:
self.highscore = self.score
self.score = 0
self.field = [[0 for i in range(self.width)] for j in range(self.height)]
self.spawn()
self.spawn()
3.一行向左合并
(注：这一操作是在 move 内定义的，拆出来是为了方便阅读)
def move_row_left(row):
def tighten(row): # 把零散的非零单元挤到一块
new_row = [i for i in row if i != 0]
new_row += [0 for i in range(len(row) - len(new_row))]
return new_row
def merge(row): # 对邻近元素进行合并
pair = False
new_row = []
for i in range(len(row)):
if pair:
new_row.append(2 * row[i])
self.score += 2 * row[i]
pair = False
else:
if i + 1 < len(row) and row[i] == row[i + 1]:
pair = True
new_row.append(0)
else:
new_row.append(row[i])
assert len(new_row) == len(row)
return new_row
#先挤到一块再合并再挤到一块
return tighten(merge(tighten(row)))
4.棋盘走一步
通过对矩阵进行转置与逆转，可以直接从左移得到其余三个方向的移动操作
def move(self, direction):
def move_row_left(row):
#一行向左合并
moves = {}
moves['Left'] = lambda field: [move_row_left(row) for row in field]
moves['Right'] = lambda field: invert(moves['Left'](invert(field)))
moves['Up'] = lambda field: transpose(moves['Left'](transpose(field)))
moves['Down'] = lambda field: transpose(moves['Right'](transpose(field)))
if direction in moves:
if self.move_is_possible(direction):
self.field = moves[direction](self.field)
self.spawn()
return True
else:
return False
5.判断输赢
def is_win(self):
return any(any(i >= self.win_value for i in row) for row in self.field)
def is_gameover(self):
return not any(self.move_is_possible(move) for move in actions)
6.判断能否移动
def move_is_possible(self, direction):
def row_is_left_movable(row):
def change(i):
if row[i] == 0 and row[i + 1] != 0: # 可以移动
return True
if row[i] != 0 and row[i + 1] == row[i]: # 可以合并
return True
return False
return any(change(i) for i in range(len(row) - 1))
check = {}
check['Left'] = lambda field: any(row_is_left_movable(row) for row in field)
check['Right'] = lambda field: check['Left'](invert(field))
check['Up'] = lambda field: check['Left'](transpose(field))
check['Down'] = lambda field: check['Right'](transpose(field))
if direction in check:
return check[direction](self.field)
else:
return False
绘制游戏界面
（注：这一步是在棋盘类内定义的）
def draw(self, screen):
help_string1 = '(W)Up (S)Down (A)Left (D)Right'
help_string2 = ' (R)Restart (Q)Exit'
gameover_string = ' GAME OVER'
win_string = ' YOU WIN!'
def cast(string):
screen.addstr(string + '\n')
#绘制水平分割线
def draw_hor_separator():
line = '+' + ('+------' * self.width + '+')[1:]
separator = defaultdict(lambda: line)
if not hasattr(draw_hor_separator, "counter"):
draw_hor_separator.counter = 0
cast(separator[draw_hor_separator.counter])
draw_hor_separator.counter += 1
def draw_row(row):
cast(''.join('|{: ^5} '.format(num) if num > 0 else '| ' for num in row) + '|')
screen.clear()
cast('SCORE: ' + str(self.score))
if 0 != self.highscore:
cast('HIGHSCORE: ' + str(self.highscore))
for row in self.field:
draw_hor_separator()
draw_row(row)
draw_hor_separator()
if self.is_win():
cast(win_string)
else:
if self.is_gameover():
cast(gameover_string)
else:
cast(help_string1)
cast(help_string2)
完成主逻辑
完成以上工作后，我们就可以补完主逻辑了！
def main(stdscr):
def init():
#重置游戏棋盘
game_field.reset()
return 'Game'
def not_game(state):
#画出 GameOver 或者 Win 的界面
game_field.draw(stdscr)
#读取用户输入得到action，判断是重启游戏还是结束游戏
action = get_user_action(stdscr)
responses = defaultdict(lambda: state) #默认是当前状态，没有行为就会一直在当前界面循环
responses['Restart'], responses['Exit'] = 'Init', 'Exit' #对应不同的行为转换到不同的状态
return responses[action]
def game():
#画出当前棋盘状态
game_field.draw(stdscr)
#读取用户输入得到action
action = get_user_action(stdscr)
if action == 'Restart':
return 'Init'
if action == 'Exit':
return 'Exit'
if game_field.move(action): # move successful
if game_field.is_win():
return 'Win'
if game_field.is_gameover():
return 'Gameover'
return 'Game'
state_actions = {
'Init': init,
'Win': lambda: not_game('Win'),
'Gameover': lambda: not_game('Gameover'),
'Game': game
}
curses.use_default_colors()
game_field = GameField(win=2048)
state = 'Init'
#状态机开始循环
while state != 'Exit':
state = state_actions[state]()
运行
填上最后一行代码：
curses.wrapper(main)
运行看看吧！
$ python3 2048.py
全部代码
#-*- coding:utf-8 -*-
import curses
from random import randrange, choice # generate and place new tile
from collections import defaultdict
letter_codes = [ord(ch) for ch in 'WASDRQwasdrq']
actions = ['Up', 'Left', 'Down', 'Right', 'Restart', 'Exit']
actions_dict = dict(zip(letter_codes, actions * 2))
def get_user_action(keyboard):
char = "N"
while char not in actions_dict:
char = keyboard.getch()
return actions_dict[char]
def transpose(field):
return [list(row) for row in zip(*field)]
def invert(field):
return [row[::-1] for row in field]
class GameField(object):
def __init__(self, height=4, width=4, win=2048):
self.height = height
self.width = width
self.win_value = win
self.score = 0
self.highscore = 0
self.reset()
def reset(self):
if self.score > self.highscore:
self.highscore = self.score
self.score = 0
self.field = [[0 for i in range(self.width)] for j in range(self.height)]
self.spawn()
self.spawn()
def move(self, direction):
def move_row_left(row):
def tighten(row): # squeese non-zero elements together
new_row = [i for i in row if i != 0]
new_row += [0 for i in range(len(row) - len(new_row))]
return new_row
def merge(row):
pair = False
new_row = []
for i in range(len(row)):
if pair:
new_row.append(2 * row[i])
self.score += 2 * row[i]
pair = False
else:
if i + 1 < len(row) and row[i] == row[i + 1]:
pair = True
new_row.append(0)
else:
new_row.append(row[i])
assert len(new_row) == len(row)
return new_row
return tighten(merge(tighten(row)))
moves = {}
moves['Left'] = lambda field: \
[move_row_left(row) for row in field]
moves['Right'] = lambda field: \
invert(moves['Left'](invert(field)))
moves['Up'] = lambda field: \
transpose(moves['Left'](transpose(field)))
moves['Down'] = lambda field: \
transpose(moves['Right'](transpose(field)))
if direction in moves:
if self.move_is_possible(direction):
self.field = moves[direction](self.field)
self.spawn()
return True
else:
return False
def is_win(self):
return any(any(i >= self.win_value for i in row) for row in self.field)
def is_gameover(self):
return not any(self.move_is_possible(move) for move in actions)
def draw(self, screen):
help_string1 = '(W)Up (S)Down (A)Left (D)Right'
help_string2 = ' (R)Restart (Q)Exit'
gameover_string = ' GAME OVER'
win_string = ' YOU WIN!'
def cast(string):
screen.addstr(string + '\n')
def draw_hor_separator():
line = '+' + ('+------' * self.width + '+')[1:]
separator = defaultdict(lambda: line)
if not hasattr(draw_hor_separator, "counter"):
draw_hor_separator.counter = 0
cast(separator[draw_hor_separator.counter])
draw_hor_separator.counter += 1
def draw_row(row):
cast(''.join('|{: ^5} '.format(num) if num > 0 else '| ' for num in row) + '|')
screen.clear()
cast('SCORE: ' + str(self.score))
if 0 != self.highscore:
cast('HIGHSCORE: ' + str(self.highscore))
for row in self.field:
draw_hor_separator()
draw_row(row)
draw_hor_separator()
if self.is_win():
cast(win_string)
else:
if self.is_gameover():
cast(gameover_string)
else:
cast(help_string1)
cast(help_string2)
def spawn(self):
new_element = 4 if randrange(100) > 89 else 2
(i,j) = choice([(i,j) for i in range(self.width) for j in range(self.height) if self.field[i][j] == 0])
self.field[i][j] = new_element
def move_is_possible(self, direction):
def row_is_left_movable(row):
def change(i): # true if there'll be change in i-th tile
if row[i] == 0 and row[i + 1] != 0: # Move
return True
if row[i] != 0 and row[i + 1] == row[i]: # Merge
return True
return False
return any(change(i) for i in range(len(row) - 1))
check = {}
check['Left'] = lambda field: \
any(row_is_left_movable(row) for row in field)
check['Right'] = lambda field: \
check['Left'](invert(field))
check['Up'] = lambda field: \
check['Left'](transpose(field))
check['Down'] = lambda field: \
check['Right'](transpose(field))
if direction in check:
return check[direction](self.field)
else:
return False
def main(stdscr):
def init():
#重置游戏棋盘
game_field.reset()
return 'Game'
def not_game(state):
#画出 GameOver 或者 Win 的界面
game_field.draw(stdscr)
#读取用户输入得到action，判断是重启游戏还是结束游戏
action = get_user_action(stdscr)
responses = defaultdict(lambda: state) #默认是当前状态，没有行为就会一直在当前界面循环
responses['Restart'], responses['Exit'] = 'Init', 'Exit' #对应不同的行为转换到不同的状态
return responses[action]
def game():
#画出当前棋盘状态
game_field.draw(stdscr)
#读取用户输入得到action
action = get_user_action(stdscr)
if action == 'Restart':
return 'Init'
if action == 'Exit':
return 'Exit'
if game_field.move(action): # move successful
if game_field.is_win():
return 'Win'
if game_field.is_gameover():
return 'Gameover'
return 'Game'
state_actions = {
'Init': init,
'Win': lambda: not_game('Win'),
'Gameover': lambda: not_game('Gameover'),
'Game': game
}
curses.use_default_colors()
# 设置终结状态最大数值为 32
game_field = GameField(win=32)
state = 'Init'
#状态机开始循环
while state != 'Exit':
state = state_actions[state]()
curses.wrapper(main)用面向对象方法重构代码
Author: protream
#-*- coding:utf-8 -*-
import random
import curses
from itertools import chain
class Action(object):
UP = 'up'
LEFT = 'left'
DOWN = 'down'
RIGHT = 'right'
RESTART = 'restart'
EXIT = 'exit'
letter_codes = [ord(ch) for ch in 'WASDRQwasdrq']
actions = [UP, LEFT, DOWN, RIGHT, RESTART, EXIT]
actions_dict = dict(zip(letter_codes, actions * 2))
def __init__(self, stdscr):
self.stdscr = stdscr
def get(self):
char = "N"
while char not in self.actions_dict:
char = self.stdscr.getch()
return self.actions_dict[char]
class Grid(object):
def __init__(self, size):
self.size = size
self.cells = None
self.reset()
def reset(self):
self.cells = [[0 for i in range(self.size)] for j in range(self.size)]
self.add_random_item()
self.add_random_item()
def add_random_item(self):
empty_cells = [(i, j) for i in range(self.size) for j in range(self.size) if self.cells[i][j] == 0]
(i, j) = random.choice(empty_cells)
self.cells[i][j] = 4 if random.randrange(100) >= 90 else 2
def transpose(self):
self.cells = [list(row) for row in zip(*self.cells)]
def invert(self):
self.cells = [row[::-1] for row in self.cells]
@staticmethod
def move_row_left(row):
def tighten(row):
new_row = [i for i in row if i != 0]
new_row += [0 for i in range(len(row) - len(new_row))]
return new_row
def merge(row):
pair = False
new_row = []
for i in range(len(row)):
if pair:
new_row.append(2 * row[i])
# self.score += 2 * row[i]
pair = False
else:
if i + 1 < len(row) and row[i] == row[i + 1]:
pair = True
new_row.append(0)
else:
new_row.append(row[i])
assert len(new_row) == len(row)
return new_row
return tighten(merge(tighten(row)))
def move_left(self):
self.cells = [self.move_row_left(row) for row in self.cells]
def move_right(self):
self.invert()
self.move_left()
self.invert()
def move_up(self):
self.transpose()
self.move_left()
self.transpose()
def move_down(self):
self.transpose()
self.move_right()
self.transpose()
@staticmethod
def row_can_move_left(row):
def change(i):
if row[i] == 0 and row[i + 1] != 0:
return True
if row[i] != 0 and row[i + 1] == row[i]:
return True
return False
return any(change(i) for i in range(len(row) - 1))
def can_move_left(self):
return any(self.row_can_move_left(row) for row in self.cells)
def can_move_right(self):
self.invert()
can = self.can_move_left()
self.invert()
return can
def can_move_up(self):
self.transpose()
can = self.can_move_left()
self.transpose()
return can
def can_move_down(self):
self.transpose()
can = self.can_move_right()
self.transpose()
return can
class Screen(object):
help_string1 = '(W)up (S)down (A)left (D)right'
help_string2 = ' (R)Restart (Q)Exit'
over_string = ' GAME OVER'
win_string = ' YOU WIN!'
def __init__(self, screen=None, grid=None, score=0, best_score=0, over=False, win=False):
self.grid = grid
self.score = score
self.over = over
self.win = win
self.screen = screen
self.counter = 0
def cast(self, string):
self.screen.addstr(string + '\n')
def draw_row(self, row):
self.cast(''.join('|{: ^5}'.format(num) if num > 0 else '| ' for num in row) + '|')
def draw(self):
self.screen.clear()
self.cast('SCORE: ' + str(self.score))
for row in self.grid.cells:
self.cast('+-----' * self.grid.size + '+')
self.draw_row(row)
self.cast('+-----' * self.grid.size + '+')
if self.win:
self.cast(self.win_string)
else:
if self.over:
self.cast(self.over_string)
else:
self.cast(self.help_string1)
self.cast(self.help_string2)
class GameManager(object):
def __init__(self, size=4, win_num=2048):
self.size = size
self.win_num = win_num
self.reset()
def reset(self):
self.state = 'init'
self.win = False
self.over = False
self.score = 0
self.grid = Grid(self.size)
self.grid.reset()
@property
def screen(self):
return Screen(screen=self.stdscr, score=self.score, grid=self.grid, win=self.win, over=self.over)
def move(self, direction):
if self.can_move(direction):
getattr(self.grid, 'move_' + direction)()
self.grid.add_random_item()
return True
else:
return False
@property
def is_win(self):
self.win = max(chain(*self.grid.cells)) >= self.win_num
return self.win
@property
def is_over(self):
self.over = not any(self.can_move(move) for move in self.action.actions)
return self.over
def can_move(self, direction):
return getattr(self.grid, 'can_move_' + direction)()
def state_init(self):
self.reset()
return 'game'
def state_game(self):
self.screen.draw()
action = self.action.get()
if action == Action.RESTART:
return 'init'
if action == Action.EXIT:
return 'exit'
if self.move(action):
if self.is_win:
return 'win'
if self.is_over:
return 'over'
return 'game'
def _restart_or_exit(self):
self.screen.draw()
return 'init' if self.action.get() == Action.RESTART else 'exit'
def state_win(self):
return self._restart_or_exit()
def state_over(self):
return self._restart_or_exit()
def __call__(self, stdscr):
curses.use_default_colors()
self.stdscr = stdscr
self.action = Action(stdscr)
while self.state != 'exit':
self.state = getattr(self, 'state_' + self.state)()
if __name__ == '__main__':
curses.wrapper(GameManager())
用面向对象方法实现的代码中，在游戏运行的过程中 SCORE 始终为 0，大家可以思考一下如何修改代码以实现正确的计分？
License
本作品在 GFDL1.2 协议下授权使用。