如何用范围填充可变参数? [英] How to fill varargs with range?

问题描述

填充可变参数的正确方法是什么?我的尝试看起来像是一次小事 拳头我构筑范围
然后我将其转换为列表
然后到intarray
然后传播

What is a proper way to fill varargs? My attempt looks like a bycile at fist i construct range
then i convert it to list
then to intarray
then spread it

m.getColumns(*((count.. count + 35).toList().toIntArray()))

其中getColums是一种将colums索引作为varargs接受的方法

where getColums is a method which accepts colums indexes as varargs

推荐答案

是的，从这个意义上说，范围实际上离数组很远，很难将它们作为vararg参数传递.

Yeah, ranges are really far from arrays in this sense, it's rather hard to pass them in as vararg parameters.

您可以创建一个函数，将它们更快地转换为IntArray实例:

You could create a function to convert them to IntArray instances one step quicker:

fun IntRange.toIntArray() = this.toList().toIntArray()

m.getColumns(*(count..count + 35).toIntArray())

此转换的优化版本稍好:

A slightly better optimized version of this conversion:

fun IntRange.toIntArray(): IntArray {
    val size = this.last - this.first + 1
    var current = this.first
    return IntArray(size) { current++ }
}

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或者您可以定义一个重载函数，该函数采用IntRange并进行转换以调用原始函数:

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Or you could define an overloaded function that takes an IntRange and does the conversion to call the original:

fun getColumns(range: IntRange) = getColumns(*range.toList().toIntArray())

同样，这也可以利用上面的转换方法以获得更好的性能:

Again, this could also make use of the conversion method above for better performance:

fun getColumns(range: IntRange) = getColumns(*range.toIntArray())

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