# [1,2,3,4]  => [2,4,6,8]
lst = [1,2,3,4]
lst2 = []
for i in lst:res = i * 2lst2.append(res)
print(lst2)# 改写
res = [i * 2 for i in range(1, 5)]
print(res)# [1,2,3,4]  => [2,8,24,64]
'''
1-> 2   乘以2的1次幂
2-> 8   乘以2的2次幂
3 -> 24 乘以2的3次幂
4 -> 64 乘以2的4次幂
'''
# 把想要的值 写在for的左侧
res = [i << i for i in range(1,5)] # 1 << 1  2 << 2 3 << 3 4<<4
print(res)

lst = [1, 2, 3, 4, 5, 6, 67, 7, 8, 98, 9]
lst2 = []
for i in lst:if i % 2 == 0:lst2.append(i)
print(lst2)# 推导式写法
res = [i for i in lst if i %2 == 0]
print(res) # 求的都是偶数

lst1 = ["邓远文","舒畅","易思","仿真枪"]
lst2 = ["张国成","王博","邱玉龙","苏传红"]
lst = []
for i in lst1:for j in lst2:res = i + '♥♥♥' +jlst.append(res)
print(lst)
# "谁 ♥♥♥ 谁"
#改写
res = [i+'♥♥♥'+j for i in lst1 for j in lst2 ]
print(res)运行结果：['邓远文♥♥♥张国成', '邓远文♥♥♥王博', '邓远文♥♥♥邱玉龙', '邓远文♥♥♥苏传红', '舒畅♥♥♥张国成', '舒畅♥♥♥王博', '舒畅♥♥♥邱玉龙', '舒畅♥♥♥苏传红', '易思♥♥♥张国成', '易思♥♥♥王博', '易思♥♥♥邱玉龙', '易思♥♥♥苏传红', '仿真枪♥♥♥张国成', '仿真枪♥♥♥王博', '仿真枪♥♥♥邱玉龙', '仿真枪♥♥♥苏传红']

lst1 = ["邓远文","舒畅","易思","仿真枪"]
lst2 = ["张国成","王博","邱玉龙","苏传红"]
lst_new = []
for i in lst1:for j in lst2:if lst1.index(i) == lst2.index(j):strvar = i+'♥♥♥'+jlst_new.append(strvar)print(lst_new)
# 推导式写法
res = [i+'♥♥♥'+j for i in lst1 for j in lst2  if lst1.index(i) == lst2.index(j)]
print(res)# ['邓远文♥♥♥张国成', '舒畅♥♥♥王博', '易思♥♥♥邱玉龙', '仿真枪♥♥♥苏传红']

#(1).{'x': 'A', 'y': 'B', 'z': 'C' } 把字典写成x=A,y=B,z=C的列表推导式
dic = {'x': 'A', 'y': 'B', 'z': 'C' }
# for  a,b in dic.items():# print(a,b)
res = [a+"="+b for a,b in dic.items() ]
print(res)# (2).把列表中所有字符变成小写  ["ADDD","dddDD","DDaa","sss"]
lst = ["ADDD","dddDD","DDaa","sss"]
res = [i.lower() for i in  lst ]
print(res)# (3).x是0-5之间的偶数,y是0-5之间的奇数 把x,y组成一起变成元组,放到列表当中
# (0 2 4 )
# (1 3 5)
# (0 1) (0 3) (0 5)
# (2 1) (2 3) (2 5)
# (4 1) (4 3) (4 5)
lst_new = []for i in range(0,6):if i % 2 == 0:for j in range(0,6):if j % 2 == 1:lst_new.append( (i,j) )print(lst_new)# 写法一
res = [(i,j) for i in range(0,6) if i % 2 == 0 for j in range(0,6) if j % 2 == 1  ]
print(res)
lst_new2 = []
for i in range(0,6):for j in range(0,6):if i % 2==0 and j %2 ==1:lst_new2.append( (i,j) )
print(lst_new2)# 写法二
res = [(i,j) for  i in range(0,6) for j  in range(0,6) if i % 2 == 0 and j % 2 == 1 ]
print(res)# (4).使用列表推导式 制作所有99乘法表中的运算
for i in range(1,10):for j in range(1,i+1):# print("%d*%d=%2d " % (i,j,i*j))print("{:d} * {:d} = {:2d} ".format(i,j,i*j) ,end="")print()# 写法一
res = ["{:d} * {:d} = {:2d} ".format(i,j,i*j) for i in range(1,10) for j in range(1,i+1)]
print(res)for i in range(9,0,-1):for j in range(1,i+1):# print("%d*%d=%2d " % (i,j,i*j))print("{:d} * {:d} = {:2d} ".format(i,j,i*j) ,end="")print()
# 写法二
res = ["{:d} * {:d} = {:2d} ".format(i,j,i*j) for i in range(9,0,-1) for j in range(1,i+1)]
print(res)'''
(5)#求M,N中矩阵和元素的乘积
# M = [ [1,2,3],
#       [4,5,6],
#       [7,8,9]  ] # N = [ [2,2,2],
#       [3,3,3],
#       [4,4,4]  ]
=>实现效果1   [2, 4, 6, 12, 15, 18, 28, 32, 36]
=>实现效果2   [[2, 4, 6], [12, 15, 18], [28, 32, 36]]
'''
M = [[1,2,3],[4,5,6],[7,8,9]]
N = [[2,2,2],[3,3,3],[4,4,4]]# M[0][0] * N[0][0] = 2
# M[0][1] * N[0][1] = 4
# M[0][2] * N[0][2] = 6# M[1][0] * N[1][0] = 12
# M[1][1] * N[1][1] = 15
# M[1][2] * N[1][2] = 18# M[2][0] * N[2][0] = 28
# M[2][1] * N[2][1] = 32
# M[2][2] * N[2][2] = 36# 效果1  # i=> 0 1 2  j=> 0 1 2 i动的慢 j动的块
res = [M[i][j] * N[i][j] for i in range(3) for j in range(3) ]
print(res) #[2, 4, 6, 12, 15, 18, 28, 32, 36]#=>实现效果2   [    [2, 4, 6], [12, 15, 18], [28, 32, 36]    ]# [] [] []
'''
第一步遍历三个空列表
[ []  for i in range(3)  ]
第二部在空列表里面在写一个推导式遍历对应的元素
[M[i][j] * N[i][j]  for j in range(3)]
'''
res = [   [M[i][j] * N[i][j]  for j in range(3)]  for i in range(3)   ]
print(res) #[[2,4,6], [], []]

运行结果：

['x=A', 'y=B', 'z=C']
['addd', 'ddddd', 'ddaa', 'sss']
[(0, 1), (0, 3), (0, 5), (2, 1), (2, 3), (2, 5), (4, 1), (4, 3), (4, 5)]
[(0, 1), (0, 3), (0, 5), (2, 1), (2, 3), (2, 5), (4, 1), (4, 3), (4, 5)]
[(0, 1), (0, 3), (0, 5), (2, 1), (2, 3), (2, 5), (4, 1), (4, 3), (4, 5)]
[(0, 1), (0, 3), (0, 5), (2, 1), (2, 3), (2, 5), (4, 1), (4, 3), (4, 5)]
1 * 1 = 1
2 * 1 = 2 2 * 2 = 4
3 * 1 = 3 3 * 2 = 6 3 * 3 = 9
4 * 1 = 4 4 * 2 = 8 4 * 3 = 12 4 * 4 = 16
5 * 1 = 5 5 * 2 = 10 5 * 3 = 15 5 * 4 = 20 5 * 5 = 25
6 * 1 = 6 6 * 2 = 12 6 * 3 = 18 6 * 4 = 24 6 * 5 = 30 6 * 6 = 36
7 * 1 = 7 7 * 2 = 14 7 * 3 = 21 7 * 4 = 28 7 * 5 = 35 7 * 6 = 42 7 * 7 = 49
8 * 1 = 8 8 * 2 = 16 8 * 3 = 24 8 * 4 = 32 8 * 5 = 40 8 * 6 = 48 8 * 7 = 56 8 * 8 = 64
9 * 1 = 9 9 * 2 = 18 9 * 3 = 27 9 * 4 = 36 9 * 5 = 45 9 * 6 = 54 9 * 7 = 63 9 * 8 = 72 9 * 9 = 81

9 * 1 = 9 9 * 2 = 18 9 * 3 = 27 9 * 4 = 36 9 * 5 = 45 9 * 6 = 54 9 * 7 = 63 9 * 8 = 72 9 * 9 = 81
8 * 1 = 8 8 * 2 = 16 8 * 3 = 24 8 * 4 = 32 8 * 5 = 40 8 * 6 = 48 8 * 7 = 56 8 * 8 = 64
7 * 1 = 7 7 * 2 = 14 7 * 3 = 21 7 * 4 = 28 7 * 5 = 35 7 * 6 = 42 7 * 7 = 49
6 * 1 = 6 6 * 2 = 12 6 * 3 = 18 6 * 4 = 24 6 * 5 = 30 6 * 6 = 36
5 * 1 = 5 5 * 2 = 10 5 * 3 = 15 5 * 4 = 20 5 * 5 = 25
4 * 1 = 4 4 * 2 = 8 4 * 3 = 12 4 * 4 = 16
3 * 1 = 3 3 * 2 = 6 3 * 3 = 9
2 * 1 = 2 2 * 2 = 4
1 * 1 = 1

[2, 4, 6, 12, 15, 18, 28, 32, 36]
[[2, 4, 6], [12, 15, 18], [28, 32, 36]]

listvar = [{"name":"王家辉","age":18,"money":10000},{"name":"王水机","age":19,"money":5100},{"name":"王鹏","age":20,"money":4800},{"name":"李站","age":21,"money":2000},{"name":"李小龙","age":180,"money":20}
]
setvar = set()
for i in listvar:if 18 <= i['age'] <= 21 and 5000 <= i['money'] <= 5500:strvar = "尊贵VIP卡老" + i["name"][0]setvar.add(strvar)else:strvar = "抠脚大汉卡老" + i['name'][0]setvar.add(strvar)
print(setvar)# 真值 if 条件表达式 else 假值
# 第一部分 for i in listvar
# 第二部分 三目运算符:"尊贵VIP卡老" + i["name"][0] if 18 <= i['age']<=21 and 5000<=i['money']<=5500 else "抠脚大汉卡老" + i['name'][0]

res = {"尊贵VIP卡老" + i["name"][0] if 18 <= i['age']<=21 and 5000<=i['money']<=5500 else "抠脚大汉卡老" + i['name'][0] for i in listvar}
print(res)运行结果：

{'抠脚大汉卡老王', '抠脚大汉卡老李', '尊贵VIP卡老王'}
{'抠脚大汉卡老王', '抠脚大汉卡老李', '尊贵VIP卡老王'}

enumerate(iterable,[start=0])
功能:枚举 ; 将索引号和iterable中的值,一个一个拿出来配对组成元组放入迭代器中
参数:iterable: 可迭代性数据 (常用:迭代器,容器类型数据,可迭代对象range) start:  可以选择开始的索引号(默认从0开始索引)
返回值:迭代器

listvar = ["马军强", "何键翰", "郑国成", "境泽年"]
it = enumerate(listvar)
from collections import Iterator,Iterable
print(isinstance(it, Iterator))
# (1) 使用next进行调用
res = next(it)#第一个
print(res
res = next(it)
print(res)#第二个
# (2) 使用for 来调用
for i in it:#第三个print(i)# 第四个
# (3) 用list瞬间得到所有数据
it = enumerate(listvar)
lst = list(it)
print(lst) #[(0, '马军强'), (1, '何键翰'), (2, '郑国成'), (3, '境泽年')]# 利用enumerate 变成字典推导式
res = {a: b for a, b in enumerate(listvar)}
print(res)# 使用dict强转迭代器
res = dict(enumerate(listvar))
print(res)# start 可以选择从第几个数值开始数数
res = dict(enumerate(listvar,start=14))
print(res)运行结果为：

True
(0, '马军强')
(1, '何键翰')
(2, '郑国成')
(3, '境泽年')
[(0, '马军强'), (1, '何键翰'), (2, '郑国成'), (3, '境泽年')]
{0: '马军强', 1: '何键翰', 2: '郑国成', 3: '境泽年'}
{0: '马军强', 1: '何键翰', 2: '郑国成', 3: '境泽年'}
{14: '马军强', 15: '何键翰', 16: '郑国成', 17: '境泽年'}

zip(iterable, ... ...)功能: 将多个iterable中的值,一个一个拿出来配对组成元组放入迭代器中iterable: 可迭代性数据 (常用:迭代器,容器类型数据,可迭代对象range)
返回: 迭代器

# (1)zip 自动配对,如果长度超出了,自动舍弃
lst1 = ["许经雄","刘五星","正路","易思"]
lst2 = ["英俊潇洒","疯牛踢躺","柔情似水","抠脚大汉",1,2,3,4]
it = zip(lst1,lst2)
print(isinstance(it,Iterator))# 使用for 搭配next 进行调用
for i in range(3):res = next(it)#1 #2 #3print(res)for i in it:#4print(i)# 利用zip实现字典推导式
res = {a:b for a,b  in zip(lst1,lst2)}
print(res)# 使用dict强转迭代器
res = dict(zip(lst1,lst2))
print(res)# (2)用两个列表 实现如下字典:
# 'hxd':'黄熊大'
# 'jzl':'将周郎'
# 'cgt':'陈桂涛'
dic1 = {'hxd':"胸大","jzl":"牛逼","cgt":"帅气"}
dic2 = {0:"黄熊大",1:"将周郎",2:"陈桂涛"}lst_keys = dic1.keys()
# print(lst_keys)
# print(isinstance(lst_keys,Iterator))
# print(isinstance(lst_keys,Iterable))
lst_values = dic2.values()
# print(lst_values)
# print(isinstance(lst_values,Iterator))
# print(isinstance(lst_values,Iterable))

it = zip(lst_keys,lst_values)
print(it)# 使用字典推导式实现
res = {a:b for a,b in it}
print(res)
# 使用dict强转迭代器实现
it = zip(lst_keys,lst_values)
res = dict(it)
print(res)运行结果为：

True
('许经雄', '英俊潇洒')
('刘五星', '疯牛踢躺')
('正路', '柔情似水')
('易思', '抠脚大汉')
{'许经雄': '英俊潇洒', '刘五星': '疯牛踢躺', '正路': '柔情似水', '易思': '抠脚大汉'}
{'许经雄': '英俊潇洒', '刘五星': '疯牛踢躺', '正路': '柔情似水', '易思': '抠脚大汉'}
<zip object at 0x0000000001EE0848>
{'hxd': '黄熊大', 'jzl': '将周郎', 'cgt': '陈桂涛'}
{'hxd': '黄熊大', 'jzl': '将周郎', 'cgt': '陈桂涛'}

#生成器本质是迭代器，允许自定义逻辑的迭代器#迭代器和生成器区别:
    迭代器本身是系统内置的.重写不了.而生成器是用户自定义的,可以重写迭代逻辑#生成器可以用两种方式创建:(1)生成器表达式  (里面是推导式,外面用圆括号)(2)生成器函数    (用def定义,里面含有yield)

# [1,2,3,4] => [4,8,12,16]
# i << 2 i乘以2的2次幂
gen = (i << 2 for i in range(1,5))
print(gen)#<generator object <genexpr> at 0x00000000021ED570>
from collections import Iterator,Iterable
print(isinstance(gen,Iterator))# True

res = next(gen)
print(res)
res = next(gen)
print(res)
res = next(gen)
print(res)
res = next(gen)
print(res)
# res = next(gen) 小心越界
# print(res)# 4 8 12 16

gen = (i << 2 for i in range(1,5))
for i in gen:print(i)# 4 8  12 16

gen = (i << 2 for i in range(1,5))
for i in range(2):res = next(gen)print(res)# 4 8

(用def定义,里面含有yield)
# yield 类似于 return
共同点在于:执行到这句话都会把值返回出去
不同点在于:yield每次返回时,会记住上次离开时执行的位置 , 下次在调用生成
器 , 会从上次执行的位置往下走而return直接终止函数,每次重头调用.
yield 6 和 yield(6) 2种写法都可以 yield 6 更像 return 6 的写法 推荐使用

'''如果函数当中包含了yield ,那么这个函数是生成器函数'''
def mygen():print("one")yield 1print("two")yield 2print("three")yield 3# 初始化生成器函数  => 返回一个生成器对象 ,简称生成器
gen = mygen()
print(isinstance(gen,Iterator))
# 调用生成器
res = next(gen)
print(res)
res = next(gen)
print(res)
res = next(gen)
print(res)
# res = next(gen)
# print(res)
'''
代码解析:
首先初始化生成器函数 返回生成器对象 简称生成器
同过next进行调用第一次调用时
print(one)
yield 1  记录当前代码执行的位置状态,添加阻塞,暂停在这一行,并返回1,等待下一次调用第二次调用时候
print(two)
yield 2  记录当前代码执行的位置状态,添加阻塞,暂停在这一行,并返回2,等待下一次调用第三次调用时候
print(three)
yield 3  记录当前代码执行的位置状态,添加阻塞,暂停在这一行,并返回3,等待下一次调用第四次调用时
因为没有yield 返回值了 所以直接报错....

如果仍然想要执行后面没走完的代码,比如95 96 ,那么要通过try ... except 异常处理来解决try:   lst = [1,2]   print(lst[99])except:   pass

### yield from : 将一个可迭代对象变成一个迭代器返回
def mygen():# yield ["陈桂涛","五金玲","张俊林"]yield from ["陈桂涛","五金玲","张俊林"]# 初始化一个生成器函数mygen  返回生成器
gen = mygen()
res = next(gen)
print(res)
res = next(gen)
print(res)
res = next(gen)
print(res)# 用生成器写斐波那契数列
# 1,1,2,3,5,8,13,21.......
def mygen(n):a = 0 b = 1i = 0while i<n:# print(b)yield ba,b = b,a+b        i+=1
gen = mygen(100000)
for  i in range(20):res  = next(gen)print(res)'''
a = 0
b = 1
a,b = b,a
'''