【LSP】迭代器解析

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6.7 迭代器可迭代对象iterable首先可以使用isinstance(对象名,Iterable)验证某一对象是否为可迭代对象# 验证字符串、元组、列表、字典、集合类型是否为可迭代对象from collections.abc import Iterableint1 = 12306str1 = "MondayTuesdaywednesdayThursdayFridaySaturdaySunday"tuple1 = ("Monday", "Tuesday", "wednesday", "Thursday", "Friday", "Saturday", "Sunday")list1 = ["Monday", "Tuesday", "wednesday", "Thursday", "Friday", "Saturday", "Sunday"]dict1 = {"Monday": "星期一", "Tuesday": "星期二", "wednesday": "星期三", "Thursday": "星期四", "Friday": "星期五", "Saturday": "星期六",         "Sunday": "星期日", }set1 = {"Monday", "Tuesday", "wednesday", "Thursday", "Friday", "Saturday", "Sunday"}print(isinstance(int1, Iterable))print(isinstance(str1, Iterable))print(isinstance(tuple1, Iterable))print(isinstance(list1, Iterable))print(isinstance(dict1, Iterable))print(isinstance(set1, Iterable))output:FalseTrueTrueTrueTrueTrue# 验证的结果是字符串、元组、列表、字典、集合类型都是可迭代对象，数值不是可迭代对象。可迭代对象的意思就是说这个实体是可迭代的，例如字符串、列表、元组、字典、集合、迭代器等等，可以用for ... in进行循环，# 那么都可用for循环进行迭代取值，以元组为例tuple1 = ("Monday", "Tuesday", "wednesday", "Thursday", "Friday", "Saturday", "Sunday")for i in tuple1:    print(i,end=',')output：Monday,Tuesday,wednesday,Thursday,Friday,Saturday,Sunday,可以使用for循环迭代的标志是每个对象内部实现了__iter__方法，验证下每个可迭代对象是否有这个方法str1 = "MondayTuesdaywednesdayThursdayFridaySaturdaySunday"tuple1 = ("Monday", "Tuesday", "wednesday", "Thursday", "Friday", "Saturday", "Sunday")list1 = ["Monday", "Tuesday", "wednesday", "Thursday", "Friday", "Saturday", "Sunday"]dict1 = {"Monday": "星期一", "Tuesday": "星期二", "wednesday": "星期三", "Thursday": "星期四", "Friday": "星期五", "Saturday": "星期六", "Sunday": "星期日", }set1 = {"Monday", "Tuesday", "wednesday", "Thursday", "Friday", "Saturday", "Sunday"}print(("__iter__" in dir(str1)))print(("__iter__" in dir(tuple1)))print(("__iter__" in dir(list1)))print(("__iter__" in dir(dict1)))print(("__iter__" in dir(set1)))output:TrueTrueTrueTrueTrue可迭代对象不是迭代器，如何变成迭代器呢？