Enumerable.Select 与 C# 中的 lambdas 的 Java 等价物是什么？
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What is the Java equivalent for Enumerable.Select with lambdas in C#?
提问by SamuelKDavis
Say I have an object in C#:
假设我在 C# 中有一个对象：
public class Person
{
public string Name{get;set;}
public int Age{get;set;}
}
To select the names from this list in C# I would do the following:
要在 C# 中从此列表中选择名称，我将执行以下操作：
List<string> names = person.Select(x=>x.Name).ToList();
How would I do the same thing in Java 8?
我将如何在 Java 8 中做同样的事情？
采纳答案by Holger
If you have a list of Persons like List<Person> persons;you can say
如果你有一个像List<Person> persons;你这样的人的名单可以说
List<String> names
=persons.stream().map(x->x.getName()).collect(Collectors.toList());
or, alternatively
或者，或者
List<String> names
=persons.stream().map(Person::getName).collect(Collectors.toList());
But collecting into a Listor other Collectionis 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 Collectionand a lot more without the need for an intermediate storage of the Strings, e.g.
但是收集到 aList或 otherCollection旨在仅在您需要这样的Collection. 否则，您将继续使用流的操作，因为您可以使用 a 做所有可以做的事情，Collection而无需中间存储Strings，例如
persons.stream().map(Person::getName).forEach(System.out::println);
