一步步教你用Python实现2048小游戏

前言

2048游戏规则：简单的移动方向键让数字叠加，并且获得这些数字每次叠加后的得分，当出现2048这个数字时游戏胜利。同时每次移动方向键时，都会在这个4*4的方格矩阵的空白区域随机产生一个数字2或者4，如果方格被数字填满了，那么就GameOver了。

主逻辑图

逻辑图解：黑色是逻辑层，蓝色是外部方法，红色是类内方法，稍后即可知道~

下面容我逐行解释主逻辑main()函数，并且在其中穿叉外部定义的函数与类。

主逻辑代码解读（完整代码见文末）

主逻辑main如下，之后的是对主函数中的一些方法的解读：

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=32)

 state = 'Init'

 #状态机开始循环
 while state != 'Exit':
 state = state_actions[state]()

逐条解读（代码框内会标注是来自外部，无标注则是来自内部）：定义主函数

def main(stdscr):

 def init():
 #重置游戏棋盘
 game_field.reset()

reset出自外部定义的类，game_field=GameField的一个方法reset：

外部：

 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()
#其中highscore为程序初始化过程中定义的一个变量。记录你win游戏的最高分数记录。

 return 'Game'

返回一个游戏进行中的状态。game_field=GameField状态在后面有定义：

主函数底部定义：

 state_actions = {
  'Init': init,
  'Win': lambda: not_game('Win'),
  'Gameover': lambda: not_game('Gameover'),
  'Game': game
 }

 def not_game(state):
 #画出 GameOver 或者 Win 的界面
 game_field.draw(stdscr)

draw是导入的类game_field=GameField中的方法：

#来自外部类
 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!'
#定义各个字符串
 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('HGHSCORE: ' + 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)
#这里面的draw方法的字函数我就不做多的解释了，很简单的一些概念。
#但是又运用到了很优秀的精简代码。
#有的地方建议去查一下python的一些高级概念，我就不做多的介绍了。

这里面的draw方法的字函数我就不做多的解释了，很简单的一些概念。

但是又运用到了很优秀的精简代码。

有的地方建议去查一下python的一些高级概念，我就不做多的介绍了。

 #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)

读取用户行为,函数来自于代码初始的定义

#来自外部定义的函数
def get_user_action(keyboard): 
 char = "N"
 while char not in actions_dict: 
 char = keyboard.getch()
 return actions_dict[char]

在结尾处，也即是主函数执行的第三步，定义了state = state_actions[state]()这一实例：

#主函数底部：
 state = 'Init'

 #状态机开始循环
 while state != 'Exit':
 state = state_actions[state]()

 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'
#game()函数的定义类似于上面已经讲过的not_game()，只是game()有了内部循环
#即如果不是Restart/Exit或者对move之后的状态进行判断，如果不是结束游戏，就一直在game()内部循环。

game()函数的定义类似于上面已经讲过的not_game() ，只是game()有了内部循环，即如果不是Restart/Exit或者对move之后的状态进行判断，如果不是结束游戏，就一直在game()内部循环。

 state_actions = {
  'Init': init,
  'Win': lambda: not_game('Win'),
  'Gameover': lambda: not_game('Gameover'),
  'Game': game
   }

 curses.use_default_colors()
 game_field = GameField(win=32)


 state = 'Init'

 #状态机开始循环
 while state != 'Exit':
 state = state_actions[state]()
#此处的意思是：state=state_actions[state] 可以看做是：
#state=init()或者state=not_game(‘Win')或者是另外的not_game(‘Gameover')/game()

此处的意思是：state=state_actions[state] 可以看做是：state=init()或者state=not_game(‘Win')或者是另外的not_game(‘Gameover')/game()

废话不多说，上一个我的成功的图，另外，可以通过设置最后几行中的win=32来决定你最终获胜的条件！

完整代码

#-*- 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 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('HGHSCORE: ' + 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()
 game_field = GameField(win=32)
 state = 'Init'
 #状态机开始循环
 while state != 'Exit':
 state = state_actions[state]()
curses.wrapper(main)

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