在 Scala 中获取子数组的正确方法是什么? [英] What is the correct way to get a subarray in Scala?

问题描述

我试图在 Scala 中获得一个子数组，但我对正确的做法有点困惑.我最想要的是你如何在 python 中做到这一点:

I am trying to get a subarray in scala, and I am a little confused on what the proper way of doing it is. What I would like the most would be something like how you can do it in python:

x = [3, 2, 1]
x[0:2]

但我很确定你不能这样做.

but I am fairly certain you cannot do this.

最明显的方法是使用 Java Arrays util 库.

The most obvious way to do it would be to use the Java Arrays util library.

import java.util.Arrays
val start = Array(1, 2, 3)
Arrays.copyOfRange(start, 0, 2)

但是在 Scala 中使用 Java 库总是让我觉得有点脏.我发现的最scalaic"的方式是

But it always makes me feel a little dirty to use Java libraries in Scala. The most "scalaic" way I found to do it would be

def main(args: List[String]) {
    val start = Array(1, 2, 3)
    arrayCopy(start, 0, 2)
}
def arrayCopy[A](arr: Array[A], start: Int, end: Int)(implicit manifest: Manifest[A]): Array[A] = {
    val ret = new Array(end - start)
    Array.copy(arr, start, ret, 0, end - start)
    ret
}

但是有更好的方法吗?

推荐答案

可以调用slice方法:

You can call the slice method:

scala> Array("foo", "hoo", "goo", "ioo", "joo").slice(1, 4)
res6: Array[java.lang.String] = Array(hoo, goo, ioo)

它在 Python 中的工作原理.

It works like in python.

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