java - Java Colt Matrix 包需要帮助

Question

谁能告诉我如何使用Colt库从矩阵中删除列？

Answer 1

没有明确的方法来删除一列，但是您可以创建一个原始矩阵的视图，其中包含除您想要删除的列之外的所有列。

/**
 * Returns a view of the original matrix that contains all rows and all columns
 * except for the specified column.
 *
 * The view is backed by the original matrix, that is, all changes to the
 * returned matrix will be reflected by the original matrix.
 *
 * @param src The matrix to have a column "removed".
 * @param colIdx The index of the column to be hidden
 *        ({@code 0 <= colIdx < src.columns()} .
 * @return A view of the original matrix with column {@code colIdx} removed.
 */
public DoubleMatrix2D hideColumn(final DoubleMatrix2D src, final int colIdx) {
    // create array of column indices to be preserved
    final int[] keepColumns = new int[src.columns() - 1];
    for (int i = 0; i < keepColumns.length; i++) {
        keepColumns[i] = ((i < colIdx) ? i : i + 1);
    }

    return src.viewSelection(null /* keep ALL rows */, keepColumns);
}