Scala:将数组放入Set或Map中的轻巧方式 [英] Scala: lightweight way to put Arrays in a Set or Map

问题描述

由于==不适用于数组，因此我无法有效地创建一组数组(或带有数组键的Map).我宁愿不承受将数组转换为Vector或List或其他东西的性能损失.是否有一种轻量级的方法来定义数组上的自然比较和哈希码，以便我可以将它们粘贴到集合中?

Since == does not work with Arrays, I cannot effectively create a Set of Arrays (or Map with Array keys). I would rather not take the performance hit of converting my Arrays to a Vector or List or something. Is there a lightweight way to define natural comparison and hashcode on Arrays so I can stick them in a Set?

推荐答案

使用

Use WrappedArray from collection.mutable. It provides proper equality for arrays with a minimal overhead. apply, update etc calls are delegated to underlying array. Also there are special classes for primitive types (e.g. WrappedArray.ofInt) to avoid boxing and unboxing.

scala> new WrappedArray.ofInt(Array(2, 3, 4))
res35: scala.collection.mutable.WrappedArray.ofInt = WrappedArray(2, 3, 4)

scala> new WrappedArray.ofInt(Array(2, 3, 4))
res36: scala.collection.mutable.WrappedArray.ofInt = WrappedArray(2, 3, 4)

scala> res35 == res36
res37: Boolean = true

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