randomforest_3.kt

// Return samples ( in form of DataFrame object ) given their indices.
fun getEntries( indices : IntArray ) : DataFrame {
    val dataFrame = DataFrame()
    data.map { column ->
        // `column` represent a Map -> ( String , ArrayList<String> )
        // column.key -> Name of the column as in the training datasets.
        // column.value -> ArrayList<String> containing the column's data.
        val columnData = ArrayList<String>()
        val values = column.value
        // Add the feature values corresponding to each index in `indices`.
        for ( index in indices ) {
            columnData.add( values[ index ] )
        }
        println( "column data ${columnData.toTypedArray().contentToString()}  , ${indices.size}")
        // Append the column to the data frame.
        dataFrame.addColumn( columnData , column.key )
    }
    return dataFrame
}