零起点Python机器学习快速入门 PDF 原书超清版

#集合的创建方式：
tang = [123,123,456,789]
#方式1，通过set()创建
tang = set(tang) 
print (tang) #{123, 456, 789}
tang = set()
tang = set([123,123,456,456,789])
print (tang) #{123, 456, 789}

#方式2
 tang = {1,1,1,3,4}

#集合的操作：
#No.1:
a = {1,2,3,4}
b = {2,3,4,5}
#取并集方式1
print (a.union(b)) #{1,2,3,4,5}
#取并集方式2
print (a|b) #{1,2,3,4,5}
a.intersection(b) #取交集,{2,3,4}
a&b #同样是取交集
a.difference(b) #得到a与b之间的差异值，a和b相比1是b中没有的，所以返回1
print (a - b) #{1}
print (b - a) #{5}

#No.2:
a = {1,2,3,4,5,6}
b = {2,3,4} 
#b是否为a的子集
b.issubset(a) #True
b <= a #True
b > a #False
a <= a #True
a = {1,2,3}
a.add(4)
print(a) #{1,2,3,4}
#对a集合做修改
a.update([4,5,6])
print (a) #{1,2,3,4,5,6}
#删除元素
a.remove(1)
print(a) #{2,3,4,5,6}
a.pop() #弹出元素
print (a) #{3,4,5,6}

#while循环
tangs = set(['tang','bo','hu'])
while tangs: #while后跟集合，表示集合中一旦没有元素就会退出循环
    tang = tangs.pop()
    print (tang)

#for循环
tangs2 = set(['xiao','bai','long'])
for name in tangs2:
    print (name)

#根据列表长度来进行循环输出
tang = [1,2,5,8,0]
for i in range(len(tang)):
    print (tang[i])

#定义函数
def print_value():
    print('你好吗')
    print('我很好')
#调用函数
print_value()

#定义带参数的函数
def add_ab(a,b):
    return (a+b)
tang = add_ab(3,5)
print (tang) #8

#定义带参数的函数,顺便给参数赋值
def add_ab(a=1,b=2):
    return (a+b)
tang = add_ab()
print (tang) #3

#接收不定个数的参数用*args
def add_number(a,*args):
    for i in args:
        a += i
    return a
print (add_number(1,2,3)) #1代表a,结果为6

#接收不定个数的键值对参数用**kwargs
def add_number2(a,**kwargs):
    for arg,value in kwargs.items():#kwargs相当于字典可以调用items方法
        print (arg,value)
add_number2(1,x=2,y=3)

##不推荐
temp = a
a = b
b = a 
##推荐
a, b = b, a # 先生成一个元组(tuple)对象，然后unpack

##不推荐
l = ['David', 'Pythonista', '+1-514-555-1234']
first_name = l[0]
last_name = l[1]
phone_number = l[2] 
##推荐
l = ['David', 'Pythonista', '+1-514-555-1234']
first_name, last_name, phone_number = l
# Python 3 Only
first, *middle, last = another_list

##不推荐
if fruit == "apple" or fruit == "orange" or fruit == "berry":
  # 多次判断 
##推荐
if fruit in ["apple", "orange", "berry"]:
  # 使用 in 更加简洁

##不推荐
colors = ['red', 'blue', 'green', 'yellow']
result = ''
for s in colors:
  result += s # 每次赋值都丢弃以前的字符串对象, 生成一个新对象 
##推荐
colors = ['red', 'blue', 'green', 'yellow']
result = ''.join(colors) # 没有额外的内存分配

##不推荐
for key in my_dict.keys():
  # my_dict[key] ... 
##推荐
for key in my_dict:
  # my_dict[key] ...
# 只有当循环中需要更改key值的情况下，我们需要使用 my_dict.keys()
# 生成静态的键值列表。

##不推荐
if my_dict.has_key(key):
  # ...do something with d[key] 
##推荐
if key in my_dict:
  # ...do something with d[key]

##不推荐
navs = {}
for (portfolio, equity, position) in data:
  if portfolio not in navs:
      navs[portfolio] = 0
  navs[portfolio] += position * prices[equity]
##推荐
navs = {}
for (portfolio, equity, position) in data:
  # 使用 get 方法
  navs[portfolio] = navs.get(portfolio, 0) + position * prices[equity]
  # 或者使用 setdefault 方法
  navs.setdefault(portfolio, 0)
  navs[portfolio] += position * prices[equity]

##不推荐
if x == True:
  # ....
if len(items) != 0:
  # ...
if items != []:
  # ... 
##推荐
if x:
  # ....
if items:
  # ...

##不推荐
items = 'zero one two three'.split()
# method 1
i = 0
for item in items:
  print i, item
  i += 1
# method 2
for i in range(len(items)):
  print i, items[i]
##推荐
items = 'zero one two three'.split()
for i, item in enumerate(items):
  print i, item

##不推荐
new_list = []
for item in a_list:
  if condition(item):
    new_list.append(fn(item)) 
##推荐
new_list = [fn(item) for item in a_list if condition(item)]

##不推荐
for sub_list in nested_list:
  if list_condition(sub_list):
    for item in sub_list:
      if item_condition(item):
        # do something... 
##推荐
gen = (item for sl in nested_list if list_condition(sl) \
      for item in sl if item_condition(item))
for item in gen:
  # do something...

##不推荐
for x in x_list:
  for y in y_list:
    for z in z_list:
      # do something for x & y 
##推荐
from itertools import product
for x, y, z in product(x_list, y_list, z_list):
  # do something for x, y, z

##不推荐
def my_range(n):
  i = 0
  result = []
  while i < n:
    result.append(fn(i))
    i += 1
  return result # 返回列表
##推荐
def my_range(n):
  i = 0
  result = []
  while i < n:
    yield fn(i) # 使用生成器代替列表
    i += 1
*尽量用生成器代替列表，除非必须用到列表特有的函数。

##不推荐
reduce(rf, filter(ff, map(mf, a_list)))
##推荐
from itertools import ifilter, imap
reduce(rf, ifilter(ff, imap(mf, a_list)))
*lazy evaluation 会带来更高的内存使用效率，特别是当处理大数据操作的时候。

##不推荐
found = False
for item in a_list:
  if condition(item):
    found = True
    break
if found:
  # do something if found... 
##推荐
if any(condition(item) for item in a_list):
  # do something if found...

=
##不推荐
class Clock(object):
  def __init__(self):
    self.__hour = 1
  def setHour(self, hour):
    if 25 > hour > 0: self.__hour = hour
    else: raise BadHourException
  def getHour(self):
    return self.__hour
##推荐
class Clock(object):
  def __init__(self):
    self.__hour = 1
  def __setHour(self, hour):
    if 25 > hour > 0: self.__hour = hour
    else: raise BadHourException
  def __getHour(self):
    return self.__hour
  hour = property(__getHour, __setHour)

##不推荐
f = open("some_file.txt")
try:
  data = f.read()
  # 其他文件操作..
finally:
  f.close()
##推荐
with open("some_file.txt") as f:
  data = f.read()
  # 其他文件操作...

##不推荐
try:
  os.remove("somefile.txt")
except OSError:
  pass
##推荐
from contextlib import ignored # Python 3 only
with ignored(OSError):
  os.remove("somefile.txt")

##不推荐
import threading
lock = threading.Lock()
lock.acquire()
try:
  # 互斥操作...
finally:
  lock.release()
##推荐
import threading
lock = threading.Lock()
with lock:
  # 互斥操作...

x,y= 10,20
print(x,y)
x,y= y,x
print(x,y)
#1 (10, 20)
#2 (20, 10)

n= 10
result= 1< n< 20
print(result)
# True
result= 1> n<= 9
print(result)
# False

def small(a,b,c):
returnaifa<= banda<= celse(bifb<= aandb<= celsec)
print(small(1,0,1))
print(small(1,2,2))
print(small(2,2,3))
print(small(5,4,3))
#Output
#0 #1 #2 #3

[m**2 if m > 10 else m**4 for m in range(50)]
#=> [0, 1, 16, 81, 256, 625, 1296, 2401, 4096, 6561, 10000, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400, 441, 484, 529, 576, 625, 676, 729, 784, 841, 900, 961, 1024, 1089, 1156, 1225, 1296, 1369, 1444, 1521, 1600, 1681, 1764, 1849, 1936, 2025, 2116, 2209, 2304, 2401]

multiStr= “select * from multi_row
where row_id < 5”
print(multiStr)
# select * from multi_row where row_id < 5

multiStr= “””select * from multi_row
where row_id < 5″””
print(multiStr)
#select * from multi_row
#where row_id < 5

multiStr= (“select * from multi_row ”
“where row_id < 5 ”
“order by age”)
print(multiStr)
#select * from multi_row where row_id < 5 order by age

testList= [1,2,3]
x,y,z= testList
print(x,y,z)
#-> 1 2 3

import threading
import socket
print(threading)
print(socket)
#1- <module ‘threading' from ‘/usr/lib/python2.7/threading.py'>
#2- <module ‘socket' from ‘/usr/lib/python2.7/socket.py'>

>>> 2+ 1
3
>>> _
3
>>> print_
3
“_” 是上一个执行的表达式的输出。

testDict= {i: i *iforiinxrange(10)}
testSet= {i *2foriinxrange(10)}
print(testSet)
print(testDict)
#set([0, 2, 4, 6, 8, 10, 12, 14, 16, 18])
#{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36, 7: 49, 8: 64, 9: 81}

import pdb
pdb.set_trace()

# Python 2
python -m SimpleHTTPServer
# Python 3
python3 -m http.server

test= [1,3,5,7]
print(dir(test))
[‘__add__', ‘__class__', ‘__contains__', ‘__delattr__', ‘__delitem__', ‘__delslice__', ‘__doc__', ‘__eq__', ‘__format__', ‘__ge__', ‘__getattribute__', ‘__getitem__', ‘__getslice__', ‘__gt__', ‘__hash__', ‘__iadd__', ‘__imul__', ‘__init__', ‘__iter__', ‘__le__', ‘__len__', ‘__lt__', ‘__mul__', ‘__ne__', ‘__new__', ‘__reduce__', ‘__reduce_ex__', ‘__repr__', ‘__reversed__', ‘__rmul__', ‘__setattr__', ‘__setitem__', ‘__setslice__', ‘__sizeof__', ‘__str__', ‘__subclasshook__', ‘append', ‘count', ‘extend', ‘index', ‘insert', ‘pop', ‘remove', ‘reverse', ‘sort']

Python 2.x.
result= (lambdak: reduce(int.__mul__,range(1,k+1),1))(3)
print(result)
#-> 6
Python 3.x.
import functools
result= (lambdak: functools.reduce(int.__mul__,range(1,k+1),1))(3)
print(result)
#-> 6

test= [1,2,3,4,2,2,3,1,4,4,4]
print(max(set(test),key=test.count))
#-> 4

import sys
x=1001
print(sys.getrecursionlimit())
sys.setrecursionlimit(x)
print(sys.getrecursionlimit())
#1-> 1000
#2-> 1001

import sys
x=1
print(sys.getsizeof(x))
#-> 24
在 Python 3.5 中
import sys
x=1
print(sys.getsizeof(x))
#-> 28

import sys
classFileSystem(object):
def __init__(self,files,folders,devices):
self.files= files
self.folders= folders
self.devices= devices
print(sys.getsizeof(FileSystem))
classFileSystem1(object):
__slots__= [‘files','folders','devices']
def __init__(self,files,folders,devices):
self.files= files
self.folders= folders
self.devices= devices
print(sys.getsizeof(FileSystem1))
#In Python 3.5
#1-> 1016
#2-> 888

#In Python 2.7 win10
#1-> 896
#2-> 1016

import sys
lprint=lambda *args:sys.stdout.write(” “.join(map(str,args)))
lprint(“python”,”tips”,1000,1001)
#-> python tips 1000 1001

t1= (1,2,3)
t2= (10,20,30)
print(dict(zip(t1,t2)))
#-> {1: 10, 2: 20, 3: 30}

print(“http://www.google.com”.startswith((“http://”,”https://”)))
print(“http://www.google.co.uk”.endswith((“.com”,”.co.uk”)))
#1-> True
#2-> True

import itertools
test= [[-1,-2],[30,40],[25,35]]
print(list(itertools.chain.from_iterable(test)))
#-> [-1, -2, 30, 40, 25, 35]

def xswitch(x):
returnxswitch._system_dict.get(x,None)
xswitch._system_dict= {‘files': 10,'folders': 5,'devices': 2}
print(xswitch(‘default'))
print(xswitch(‘devices'))
#1-> None
#2-> 2

class MyClass:
 def __init__(self, var_a, var_b):
 self.var_a = var_a
 self.var_b = var_b

@dataclass
class MyClass:
 var_a: str
 var_b: str

response = requests.get('https://swapi.co/api/films/1/')
dictionary = response.json()

{
 'characters': ['https://swapi.co/api/people/1/',… ],
 'created': '2014-12-10T14:23:31.880000Z',
 'director': 'George Lucas',
 'edited': '2015-04-11T09:46:52.774897Z',
 'episode_id': 4,
 'opening_crawl': 'It is a period of civil war.\r\n … ',
 'planets': ['https://swapi.co/api/planets/2/', … ],
 'producer': 'Gary Kurtz, Rick McCallum',
 'release_date': '1977-05-25',
 'species': ['https://swapi.co/api/species/5/',…],
 'starships': ['https://swapi.co/api/starships/2/',…],
 'title': 'A New Hope',
 'url': 'https://swapi.co/api/films/1/',
 'vehicles': ['https://swapi.co/api/vehicles/4/',…]

class StarWarsMovie:
 def __init__(self,
   title: str,
   episode_id: int,
   opening_crawl: str,
   director: str,
   producer: str,
   release_date: datetime,
   characters: List[str],
   planets: List[str],
   starships: List[str],
   vehicles: List[str],
   species: List[str],
   created: datetime,
   edited: datetime,
   url: str
   ):

 self.title = title
 self.episode_id = episode_id
 self.opening_crawl= opening_crawl
 self.director = director
 self.producer = producer
 self.release_date = release_date
 self.characters = characters
 self.planets = planets
 self.starships = starships
 self.vehicles = vehicles
 self.species = species
 self.created = created
 self.edited = edited
 self.url = url

 if type(self.release_date) is str:
  self.release_date = dateutil.parser.parse(self.release_date)

 if type(self.created) is str:
  self.created = dateutil.parser.parse(self.created)

 if type(self.edited) is str:
  self.edited = dateutil.parser.parse(self.edited)

@dataclass
class StarWarsMovie:
 title: str
 episode_id: int
 opening_crawl: str
 director: str
 producer: str
 release_date: datetime
 characters: List[str]
 planets: List[str]
 starships: List[str]
 vehicles: List[str]
 species: List[str]
 created: datetime
 edited: datetime
 url: str

def __post_init__(self):
 if type(self.release_date) is str:
  self.release_date = dateutil.parser.parse(self.release_date)

 if type(self.created) is str:
  self.created = dateutil.parser.parse(self.created)

 if type(self.edited) is str:
  self.edited = dateutil.parser.parse(self.edited)

@dataclass(init=True, repr=True, eq=True, order=False, unsafe_hash=False, frozen=False)

#!coding=utf-8 
registry = {} 
def register(cls): 
  registry[cls.__clsid__] = cls 
  return cls 
@register 
class Foo(object): 
  __clsid__ = '123-456' 
  def bar(self): 
    pass 
print registry 

def cache(func):
  data = {}
  def wrapper(*args, **kwargs):
    key = f'{func.__name__}-{str(args)}-{str(kwargs)})'
    if key in data:
      result = data.get(key)
      print('cached')
    else:
      result = func(*args, **kwargs)
      data[key] = result
      print('calculated')
    return result
  return wrapper

@cache
def rectangle_area(length, width):
  return length * width
rectangle_area(2, 3)
# calculated
# 6
rectangle_area(2, 3)
# cached
# 6

class Cache:
  def __init__(self, func):
    self.func = func
    self.data = {}
  def __call__(self, *args, **kwargs):
    func = self.func
    data = self.data
    key = f'{func.__name__}-{str(args)}-{str(kwargs)})'
    if key in data:
      result = data.get(key)
      print('cached')
    else:
      result = func(*args, **kwargs)
      data[key] = result
      print('calculated')
    return result

@Cache
def rectangle_area(length, width):
  return length * width
rectangle_area(2, 3)
# calculated
# 6
rectangle_area(2, 3)
# cached
# 6

class Rectangle:
  def __init__(self, length, width):
    self.length = length
    self.width = width
  @cache
  def area(self):
    return self.length * self.width
r = Rectangle(2, 3)
r.area()
# calculated
# 6
r.area()
# cached
# 6

class Rectangle:
  def __init__(self, length, width):
    self.length = length
    self.width = width
  @Cache
  def area(self):
    return self.length * self.width
r = Rectangle(2, 3)
r.area()
# TypeError: area() missing 1 required positional argument: 'self'
Rectangle.area
# <__main__.Cache object at 0x0000012D8E7A6D30>
r.area
# <__main__.Cache object at 0x0000012D8E7A6D30>

class Rectangle:
  def __init__(self, length, width):
    self.length = length
    self.width = width

  def area(self):
    return self.length * self.width

Rectangle.area
# <function Rectangle.area at 0x0000012D8E7B28C8>
r = Rectangle(2, 3)
r.area
# <bound method Rectangle.area of <__main__.Rectangle object

# 定义一个简单的装饰器，什么也不做，仅仅是把可调用对象包装成函数
def method(call):
  def wrapper(*args, **kwargs):
    return call(*args, **kwargs)
  return wrapper
class Rectangle:
  def __init__(self, length, width):
    self.length = length
    self.width = width
  @method
  @Cache
  def area(self):
    return self.length * self.width
r = Rectangle(2, 3)
r.area()
# calculated
# 6
r.area()
# cached
# 6

class Rectangle:
  def __init__(self, length, width):
    self.length = length
    self.width = width
  @property
  @Cache
  def area(self):
    return self.length * self.width
r = Rectangle(2, 3)
r.area
# calculated
# 6
r.area
# cached
# 6

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]()

def main(stdscr):

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

 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)

#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。

 #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)

#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]

#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。

 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()

#-*- 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)