Python实现小游戏--2048

正文

本次是我对于Python实现2048这个曾经风靡一时的小游戏的代码解读



工作环境

一、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~



状态机。。。游戏概念，出自实验楼

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。

二、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()

结束语

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！



2048.gif

三、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)