Kotlin二维数组计算mean by column

fun calculateColumnMean(matrix: Array<DoubleArray>): DoubleArray {
    val rowCount = matrix.size
    val colCount = matrix[0].size
    val columnMeans = DoubleArray(colCount)

    for (j in 0 until colCount) {
        var sum = 0.0
        for (i in 0 until rowCount) {
            sum += matrix[i][j]
        }
        columnMeans[j] = sum / rowCount
    }

    return columnMeans
}

// 示例使用
val matrix = arrayOf(
    doubleArrayOf(1.0, 2.0, 3.0),
    doubleArrayOf(4.0, 5.0, 6.0),
    doubleArrayOf(7.0, 8.0, 9.0)
)

val means = calculateColumnMean(matrix)
println(means.joinToString()) // 输出: 4.0, 5.0, 6.0

fun calculateColumnMean(matrix: Array<DoubleArray>): DoubleArray {
    if (matrix.isEmpty() || matrix[0].isEmpty()) {
        throw IllegalArgumentException("Matrix is empty or has empty columns")
    }
    // ... 剩余代码 ...
}

fun calculateColumnMean(matrix: Array<IntArray>): DoubleArray {
    val rowCount = matrix.size
    val colCount = matrix[0].size
    val columnMeans = DoubleArray(colCount)

    for (j in 0 until colCount) {
        var sum = 0.0
        for (i in 0 until rowCount) {
            sum += matrix[i][j].toDouble()
        }
        columnMeans[j] = sum / rowCount
    }

    return columnMeans
}