如何仅在 Kotlin 中对第一级二维数组进行洗牌答案

【问题标题】：How to shuffle 2 dimensional array at first level only in Kotlin如何仅在 Kotlin 中对第一级二维数组进行洗牌
【发布时间】：2020-01-25 06:13:52
【问题描述】：

我有一个二维数组Array<Array<Int>>，我只想在第一级洗牌，但我没有成功。

contentTitle = arrayOf(
                arrayOf(R.drawable.ic_fathah1_1, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_2, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_3, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_4, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_5, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_6, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_7, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_8, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_9, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_10, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_11, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_12, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_13, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_14, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_15, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_16, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_17, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_18, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_19, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_20, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_21, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_22, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_23, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_24, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_25, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_26, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_27, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_28, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_29, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_30, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_31, R.raw.ahem_x)
            )
            contentTitle.shuffle()

我用谷歌搜索了这个问题，只发现了可变列表的改组。如何为我的第一级数组实现简单的随机播放？

【问题讨论】：

随机播放扩展不适用于数组。也许您应该将其转换为列表，然后对其进行随机播放，然后将其转换为数组。 contentTitle.asList().shuffled().toTypedArray()
@RaminBoodaghi 我对此很陌生。你能告诉我当前数组的上下文吗？
查看我的答案：stackoverflow.com/a/59907306/3144323

标签： android arrays kotlin

【解决方案1】：

不幸的是，目前还没有数组的shuffle() 实现。请参阅此处的discussion 和相关的issue。目前您可以添加自己的实现，例如：

fun Array.shuffle(rnd: java.util.Random) {
    // Fisher-Yates shuffle algorithm
    for (i in this.size - 1 downTo 1) {
        val j = rnd.nextInt(i + 1)
        val temp = this[i]
        this[i] = this[j]
        this[j] = temp
    }
}

基于MutableList.shuffle()实现的实现，你可以找到here。

另一种解决方案可能是将数组转换为列表，将其打乱并转换回来，但这是低效的方法：

val array = arrayOf(1, 2, 3, 4)
val shuffledArray = array
    .toMutableList()
    .apply { shuffle() }
    .toTypedArray()

【讨论】：

【解决方案2】：

将您的array 转换为MutableList，然后随机播放列表。

在您的情况下，不要直接创建二维数组，而是尝试创建一个 MutableList 来保存您所有的 Int 数组

var mutableList = mutableListOf(
            arrayOf(1,2,3,4),
            arrayOf(5,6,7,8),
            arrayOf(9,10,11,12),
            arrayOf(13,14,15,16))

一旦你有了MutableList，你就可以使用shuffle函数

mutableList.shuffle()

改组后将MutableList 转换为二维数组使用

 var arr = mutableList.toTypedArray()

【讨论】：

这是一个很好的解决方案，除非性能是一个问题。如果您使用的是数组而不是列表，那么这是一个主要的性能损失

【解决方案3】：

随机播放扩展不适用于数组。也许您应该将其转换为列表，然后对其进行随机播放，然后将其转换为数组

contentTitle = arrayOf(
                arrayOf(R.drawable.ic_fathah1_1, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_2, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_3, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_4, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_5, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_6, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_7, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_8, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_9, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_10, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_11, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_12, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_13, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_14, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_15, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_16, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_17, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_18, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_19, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_20, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_21, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_22, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_23, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_24, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_25, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_26, R.raw.ahem_x),
                arrayOf(R.drawable.ic_fathah1_27, R.raw.bad_disk_x),
                arrayOf(R.drawable.ic_fathah1_28, R.raw.baseball_hit),
                arrayOf(R.drawable.ic_fathah1_29, R.raw.bloop_x),
                arrayOf(R.drawable.ic_fathah1_30, R.raw.blurp_x),
                arrayOf(R.drawable.ic_fathah1_31, R.raw.ahem_x)
            ).asList().shuffled().toTypedArray()

【讨论】：