# 定義一個(gè)列表，列表是可迭代對(duì)象
lst = [1, 2, 3, 4, 5]

# 獲取列表的所有成員
res_lst = dir(lst)

print(res_lst)
'''
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']
'''

# 查看是否存在__iter__方法
res = '__iter__' in res_lst

print(res)  # True

# 存在__iter__方法，說明確實(shí)是一個(gè)可迭代對(duì)象

lst = [1, 2, 3]
print(type(lst))    # <class 'list'>
it = iter(lst)
print(type(it))     # <class 'list_iterator'>

lst = [1, 2, 3]
print(type(lst))    # <class 'list'>
it = lst.__iter__()
print(type(it))     # <class 'list_iterator'>

# 列表
lst = list()

# 迭代器
lst_it = iter(lst)

# 迭代器中的所有成員
res_lst = dir(lst_it)

# 判斷
if '__iter__' in res_lst:
	print('lst_it是一個(gè)可迭代對(duì)象')

if '__next__' in res_lst:
	print('lst_it是一個(gè)迭代器')

'''
結(jié)果：
lst_it是一個(gè)可迭代對(duì)象
lst_it是一個(gè)迭代器
'''

lst = list()

lst_it = iter(lst)

# 判斷是否是迭代器
res = isinstance(lst_it, Iterator)
print(res)  # True

# 判斷是否是可迭代對(duì)象
res = isinstance(lst_it, Iterable)
print(res)  # True

# 因?yàn)閘st本沒有數(shù)據(jù)，所以無法取出數(shù)據(jù)
lst = list()
lst_it = iter(lst)
res = next(lst_it)  # StopIteration
print(res)

lst = [1, 2, 3]

lst_it = iter(lst)

# 迭代器中一次只會(huì)取出一個(gè)數(shù)據(jù)
print(next(lst_it))  # 1
print(next(lst_it))  # 2
print(next(lst_it))  # 3

# 超出迭代器中的元素個(gè)數(shù)，就會(huì)報(bào)錯(cuò)
print(next(lst_it))  # StopIteration

# 如果要重新取出數(shù)據(jù)，就重置迭代器，重新定義一邊迭代器就是重置迭代器
lst_it = iter(lst)

# 再次取出數(shù)據(jù)，使用__next__方法
print(lst_it.__iter__())  # 1
print(lst_it.__iter__())  # 2
print(lst_it.__iter__())  # 3