foreach和map之间有区别吗? [英] Is there a difference between foreach and map?

问题描述

好吧，这更多是计算机科学问题，而不是基于特定语言的问题，但是map操作和foreach操作之间有区别吗?还是它们只是同一事物的不同名称?

Ok this is more of a computer science question, than a question based on a particular language, but is there a difference between a map operation and a foreach operation? Or are they simply different names for the same thing?

推荐答案

不同.

foreach遍历列表，并对每个列表成员进行一些具有副作用的操作(例如，将每个保存到数据库中)

foreach iterates over a list and applies some operation with side effects to each list member (such as saving each one to the database for example)

map遍历一个列表，转换该列表的每个成员，并返回与转换后的成员大小相同的另一个列表(例如将字符串列表转换为大写字母)

map iterates over a list, transforms each member of that list, and returns another list of the same size with the transformed members (such as converting a list of strings to uppercase)

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