如何从列表中筛选出无选项? [英] How to filter None's out of List[Option]?

问题描述

如果我在Scala中有一个List[Option[A]]，那么过滤掉None值的惯用方式是什么?

If I have a List[Option[A]] in Scala, what is the idiomatic way to filter out the None values?

一种方法是使用以下内容:

One way is to use the following:

val someList: List[Option[String]] = List(Some("Hello"), None, Some("Goodbye"))
someList.filter(_ != None)

还有更惯用的方式吗?这看起来确实很简单.

Is there a more "idiomatic" way? This does seem pretty simple.

推荐答案

如果要同时删除这些选项，则可以使用flatten:

If you want to get rid of the options at the same time, you can use flatten:

scala> someList.flatten
res0: List[String] = List(Hello, Goodbye)

这篇关于如何从列表中筛选出无选项?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！