Python3 生成器

'''
列表生成式
'''

# a1 = [x for x in range(10)]
# a2 = [x*2 for x in range(10)]
# print(a1)
# print(a2)
#
# def fun1(x):
#     return x**3
# a3 = [fun1(x) for x in range(10)]
# print(a3)
#
# # 列表生成式
# # 取值方式
# b = ['asd',8,9,10]
# w,x,y,z = b
# print(w,x,y,z)
# print(b)
#
#
# # 生成器
# c = (x*2 for x in range(10))        # c是生成器对象
# print(c)        # <generator object <genexpr> at 0x00000286BEF21CA8>
# # print(next(c))  # 等价于 c.__next__()，在Python2中等价于 c.next()
# # print(next(c))
# # print(next(c))
# # print(next(c))  # 超出范围会报错
#
# # 生成器是可迭代对象
# import time
# for i in c:     # for 对c进行了一个next（）的功能
#     print(i)
#     # time.sleep(1)

'''
生成器的两种创建方式
1.(x*2 for x in range(10))
2.yield
'''

# def fun2():
#     print('###')    # 此打印没有显示
#     yield 1
# print(fun2())       # fun2()是生成器对象
#
# def fun3():
#     print('###')
#     yield 1
#
#     print('asd')
#     yield 2
#
#     return None
#
# c1 = fun3()
# # next(c1)      # next（）被返回1
# # next(c1)      # next（）被返回2
#
# for i in fun3():
#     print(i)    # ‘###’， 1， ‘asd', 2
#                 # 此时的1,2是上面的返回值


'''
什么是可迭代对象,可迭代对象拥有iter方法
'''

# list1 = [1,2,3]
# list1.__iter__()
#
# tup1 = (1,2,3)
# tup1.__iter__()
#
# disc1 = {'asd':123}
# disc1.__iter__()



# # 斐波那契数列
# # 0 1 1 2 3 5 8 13 21 34
# def fun4(max):
#     q,before,after = 0,0,1
#     while q < max:
#         print(after)
#         before,after = after,before+after
#         q += 1
# fun4(10)
# print(fun4(8))

# # 使用生成器创建斐波那契数列
# def fun5(max):
#     q,before,after = 0,0,1
#     while q < max:
#
#         yield before
#         before,after = after,before+after
#         q = q + 1
# z = fun5(8)
# print(z)
# print(next(z))
# print(next(z))
# print(next(z))
# print(next(z))
# print(next(z))


'''
send 方法
'''
# def fun5():
#     print('a1')
#     a = yield 1
#     print(a)
# 
#     yield 2
# x = fun5()
# x1 = x.send(None)       # 等价于next(x)
#                         # 第一次send前没有next，只能传一个send（None）
# h = x.send('aaaaaaaaa')
# print(h)

'''
send 比 next 多一个功能，是可以传入一个参数给其中的变量

'''