如何在Kotlin中对列表进行分区和类型转换 [英] How to partition and typecast a List in Kotlin

问题描述

在Kotlin中，我可以:

In Kotlin I can:

val (specificMembers, regularMembers) = members.partition {it is SpecificMember}

据我所知我不能做类似的事情:

However to my knowledge I can not do something like:

val (specificMembers as List<SpecificMember>, regularMembers) = members.partition {it is SpecificMember}

我的问题是-是否有一种惯用的方法来按类对iterable进行分区，并在需要时将这些已分区的部分类型转换.

My question would be - is there's an idiomatic way to partition iterable by class and typecast it those partitioned parts if needed.

推荐答案

partition函数将返回Pair<List<T>, List<T>>，其中T是Iterable的通用类型.您可以使用以下方法再次转换分区值: let:

The partition function will return a Pair<List<T>, List<T>> with T being the generic type of your Iterable. You can transform the partitioned values again using e.g. let:

val (specificMembers, regularMembers) = lists
    .partition { it is SpecificMember }
    .let { Pair(it.first as List<SpecificMember>, it.second) }

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