Scala-创建指定长度的类型参数化数组 [英] Scala - creating a type parametrized array of specified length

问题描述

如果在Scala IDE中，请尝试以下操作:

If in Scala IDE try the following:

val chars = Array[Char](256)

一切都很好.但是，如果我这样做:

it is all fine. But if I do this:

val len = 256
val chars = Array[Char](len)

它说它期望一个Char而不是len吗?为什么?我希望行为是一样的！为什么它认为我要把那个东西放到数组中而不是指定它的大小?据我所知，没有用于数组的构造函数，只需一个参数即可将其放置在数组中.

it says that it expects a Char instead of len? Why? I expect the behavior to be the same! Why does it think that I want to put that thing in the array instead of specifying it's size? As far as I know, there is no constructor for arrays that takes a single argument to place it inside the array.

推荐答案

val chars = Array[Char](256)

之所以有效，是因为256被视为Char，它会创建一个元素数组(代码为256)

This works because 256 treated as a Char and it creates one-element array (with code 256)

val len = 256
val chars = Array[Char](len)

这里len是Int，所以失败了

Here len is Int, so it fails

要创建指定大小的数组，您需要像这样的

To create array of specified size you need something like this

val chars = Array.fill(256){0}

其中{0}是产生元素的函数

如果数组的内容无关紧要，您也可以使用new代替fill:

If the contents of the Array don't matter you can also use new instead of fill:

val chars = new Array[Char](256)

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