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python基础之迭代器和生成器

2024-09-14 03:06:27   217人阅读

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迭代器

作用:不依靠索引遍历,可遍历无索引对象

特性:分批次取值,比有索引对象更节省内存


缺点:无法获取迭代器的长度

    使用不如列表索引灵活

    一次性的,只能从头到尾取值


判断:只要本身有__iter__方法,就是可迭代的




try :               #异常退出,for 循环自带检测

    dadada

except StopIteration:

    break

生成器

简单定义:生成器就是一个函数 包含 yield 语句

特性:分步运行函数,能够保存函数当前状态

与return的区别 :return 只能返回一次,yield可以返回多次值

yield

把函数变成生成器(生成器本身也是迭代器)

用yield 可以返回多次

函数在暂停以及下一次继续下一次运行状态有yield保存

python基础之迭代器和生成器


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