【8.2】什么是迭代器和可迭代對象

#!/user/bin/env python
# -*- coding:utf-8 -*-

from collections.abc import Iterator


class Company:
    def __init__(self, employee_list):
        self.employee = employee_list

    def __iter__(self):
        return MyIterator(self.employee)


class MyIterator(Iterator):
    def __init__(self, employee_list):
        self.iter_list = employee_list
        self.index = 0

    def __next__(self):
        # 真正返回迭代值的邏輯
        try:
            word = self.iter_list[self.index]
        except IndexError:
            raise StopIteration
        self.index += 1
        return word


if __name__ == '__main__':
    company = Company(['tom', 'bob', 'jane'])
    my_itor = iter(company)
    while True:
        try:
            print(next(my_itor))
        except StopIteration:
            print('迭代完成')

tom
bob
jane
迭代完成

 

可迭代對象

　　可以被 for in 遍歷的對象

迭代器：

　　迭代器是一個對象

　　迭代器只能使用一次

　　迭代器一定是一個可迭代對象，可迭代對象不一定是一個迭代器，迭代器是一個對象class