from collections.abc import Iterable
a: int = 1
print(isinstance(a, Iterable))  # False
b: str = "lalalalala" 
print(isinstance(b, Iterable))  # True
c: set = set([1, 2])
print(isinstance(c, Iterable))  # True

class MyIterable:
	def __iter__(self):
		pass
print(isinstance(MyIterable(), Iterable)) # True

from collections.abc import Iterator, Iterable
class MyIterator:
	def __init__(self, array_list):
		self.array_list = array_list
		self.index = 0
	def __iter__(self):
		return self
	def __next__(self):
		if self.index < len(self.array_list):
			val = self.array_list[self.index]
			self.index += 1
			return val
		else:
			raise StopIteration
# 父類如果是迭代器，子類也將是迭代器
class MySubIterator(MyIterator):
	def __init__(self):
		pass
myIterator = MyIterator([1, 2, 3, 4])
# 判斷是否為可迭代對(duì)象
print(isinstance(myIterator, Iterable))  # True
# 判斷是否為迭代器
print(isinstance(myIterator, Iterator))  # True
# 子類實(shí)例化
mySubIterator = MySubIterator()
print(isinstance(mySubIterator, Iterator))  # True
# 進(jìn)行迭代
print(next(myIterator))  # 1
print(next(myIterator))  # 2
print(next(myIterator))  # 3
print(next(myIterator))  # 4
print(next(myIterator))  # raise StopIteration

 - 優(yōu)點(diǎn)：迭代器對(duì)象表示的是一個(gè)數(shù)據(jù)流，可以在需要時(shí)才去調(diào)用next來獲取一個(gè)值；因而本身在內(nèi)存中始終只保留一個(gè)值，對(duì)于內(nèi)存占用小可以存放無限數(shù)據(jù)流。優(yōu)于其他容器需要一次將所有元素都存放進(jìn)內(nèi)存，如：列表、集合、字典...等
 - 缺點(diǎn)：1.無法獲取存放的元素長(zhǎng)度，除非取完計(jì)數(shù)。2.只能向后取值，next()永遠(yuǎn)返回的是下一個(gè)值。取值不靈活，無法取出指定值(無法像字典的key,或列表的下標(biāo))，而且迭代器的生命周期是一次性的元素被迭代完則生命周期結(jié)束

# 列表生成式
_list = [i for i in range(10)]
print(type(_list))  # <class 'list'>
print(_list)  # [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
# 生成器
_generator = (i for i in range(10))
print(type(_generator))  # <class 'generator'>
print(_generator)  # <generator object <genexpr> at 0x7fbcd92c9ba0>
# 生成器對(duì)象取值
print(_generator.__next__())  # 0
print(next(_generator)) # 1
# 注意從第三個(gè)元素開始了！
for x in _generator:
	print(x)  # 2，3，4，5，6，7，8，9

def gen_generator():
	yield 1
def generator():
	return 1
print(gen_generator(), type(gen_generator()))  
# <generator object gen_generator at 0x7fe68b2c8b30> <class 'generator'>
print(generator(), type(generator()))  
# 1 <class 'int'>

def gen_generator2():
	yield [1, 2, 3]
s = gen_generator2()
print(next(s))  # [1, 2, 3]

def consumer():
	r = ''
	while True:
		n = yield r
		if not n:
			return
		print(f'[CONSUMER] Consuming get params.. ({n})')
		if n == 3:
			r = '500 Error'
		else:
			r = '200 OK'
def produce(c):
	c.send(None)  # 啟動(dòng)生成器
	n = 0
	while n < 5:
		n = n + 1
		print(f'[PRODUCER] Producing with params.. ({n})')
		r = c.send(n)  # 一旦n有值，則切換到consumer執(zhí)行
		print(f'[PRODUCER] Consumer return : [{r}]')
		if not r.startswith('200'):
			print("消費(fèi)者返回服務(wù)異常，則結(jié)束生產(chǎn)，并關(guān)閉消費(fèi)者")
			c.close()  # 關(guān)閉生成器
			break
consume = consumer()
produce(consume)
# [PRODUCER] Producing with params.. (1)
# [CONSUMER] Consuming get params.. (1)
# [PRODUCER] Consumer return : [200 OK]
# [PRODUCER] Producing with params.. (2)
# [CONSUMER] Consuming get params.. (2)
# [PRODUCER] Consumer return : [200 OK]
# [PRODUCER] Producing with params.. (3)
# [CONSUMER] Consuming get params.. (3)
# [PRODUCER] Consumer return : [500 Error]
# 消費(fèi)者返回服務(wù)異常，則結(jié)束生產(chǎn)，并關(guān)閉消費(fèi)者