【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 + '
')
        
        #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)