在C#中，带有lambdas的Enumerable.Select的Java等效项是什么? [英] What is the Java equivalent for Enumerable.Select with lambdas in C#?

问题描述

说我在C#中有一个对象:

Say I have an object in C#:

public class Person
{
    public string Name{get;set;}
    public int Age{get;set;}
}

要在C#中从此列表中选择名称，请执行以下操作:

To select the names from this list in C# I would do the following:

List<string> names = person.Select(x=>x.Name).ToList();

在Java 8中我将如何做同样的事情?

How would I do the same thing in Java 8?

推荐答案

如果您有诸如List<Person> persons;之类的人物列表，您可以说

If you have a list of Persons like List<Person> persons; you can say

List<String> names
  =persons.stream().map(x->x.getName()).collect(Collectors.toList());

或者，或者

List<String> names
  =persons.stream().map(Person::getName).collect(Collectors.toList());

，但是收集到List或其他Collection的意图是仅在需要这样的Collection的情况下才与旧版API一起使用.否则，您将继续使用流的操作，因为您可以使用Collection完成所有操作，而无需中间存储String例如

But collecting into a List or other Collection is intented to be used with legacy APIs only where you need such a Collection. Otherwise you would proceed using the stream’s operations as you can do everything you could do with a Collection and a lot more without the need for an intermediate storage of the Strings, e.g.

persons.stream().map(Person::getName).forEach(System.out::println);

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