#-----列表生成器-----
1 a = [x*2 for x in range(10)]
2 print(a,type(a)) #[0, 2, 4, 6, 8, 10, 12, 14, 16, 18] <class 'list'>
3
4 def f(n):
5 return n**3
6
7 a = [f(x) for x in range(10)]
8 print(a,type(a)) #[0, 1, 8, 27, 64, 125, 216, 343, 512, 729] <class 'list'>
#-----简单赋值方式
1 t = (12,45)
2 a,b = t
3 print(a)#12
4 print(b)#45
#----生成器(生成器就是可迭代对象)-----
1 s = (x*2 for x in range(10))
2 for i in s:
3 print(i,end=" ") # 0 2 4 6 8 10 12 14 16 18
4
5 #可迭代对象 ：内部有iter 方法
6 a = (1,2,3,5)
7 a.__iter__()
8 b = [2,3,4,5]
9 b.__iter__()
10 c = {"a":"d","g":"r"}
11 c.__iter__()
12 e = set(a)
13 print(e,type(e))
14 e.__iter__()
#-----yield关键字生成斐波那契数列
1 def fib(max):
2 n,before,after = 0,0,1
3 while n < max:
4 yield after
5 before,after = after,before+after
6 n += 1
7
8 g = fib(6)
9 for i in g:
10 print(i)
#-----yield 使用
1 def bar():
2 print("ok1")
3 str1 = yield 1
4 print(str1)
5
6 print("ok2")
7 str2 = yield 2
8 print(str2)
9 b = bar()
10 next(b)
11 ret = b.send("ee")
12 print(ret)
#-----还可通过yield实现在单线程的情况下实现并发运算的效果
1 import time
2
3 def tourist(name):
4 print("%s 开始吃包子" % name)
5 while True:
6 baozi = yield #生成器函数(generator)
7 print("%s吃了第%s个" % (name, baozi))
8
9 def cook(name):
10 c1 = tourist("A")
11 c2 = tourist("B")
12 c1.__next__()
13 c2.__next__()
14 print("%s开始做包子了" % name)
15 for i in range(1,10):
16 time.sleep(0.2)
17 c1.send(i)
18 c2.send(i)
19 cook("dream")
View Code#-----迭代器-----
1、有iter方法
2、有next方法
1 a = ["dream","rise","happy"]
2 d = iter(a) #<list_iterator object at 0x000001E01BFADA90>
3 print(d)
4 print(a.__iter__())#<list_iterator object at 0x00000258F8392668>