【python】2048

来源：https://www.shiyanlou.com/courses/368

实验楼的2048程序，在linux下可实现通过终端游戏。

主要学习的知识点：

1.状态机函数实现，用字典将状态和函数相对应，返回状态再通过字典调用相关函数

2.字典的值可以是函数名，也可以是lambda匿名函数。 lambda:25 这种是没有输入的匿名函数

3.defaultdict可以指定字典默认类型

4.hasattr可以查找是否有指定属性

5.函数可以定义在函数中，如果一个函数A只在函数B中使用，可以在B中定义A

6. 注意如下写法

choice([(i,j) for i in range(self.width) for j in range(self.height) if self.field[i][j] == 0])

7. zip, any函数的使用

8. 如果有函数A，则可以定义A.var这样的变量。在代码中可以实现类似C的静态变量的效果。

import curses  #?
from random import randrange, choice
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 = 2048
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): #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)))

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')

#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)
def spawn(self): #随机生成一个2或者4
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):
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
def main(stdscr):

def init():
#重置游戏
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'
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):#成功移动了一步
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)