ph-math/src/main/java/com/helger/numbercruncher/matrix/Matrix.java
public ColumnVector getColumn (final int c) throws MatrixException
  {
    if ((c < 0) || (c >= m_nCols))
    {
      throw new MatrixException (MatrixException.INVALID_INDEX);
    }

    final ColumnVector cv = new ColumnVector (m_nRows);
    for (int r = 0; r < m_nRows; ++r)
    {
      cv.m_aValues[r][0] = m_aValues[r][c];
    }

    return cv;
  }
public ColumnVector getColumn (final int c) throws MatrixException
  {
    if ((c < 0) || (c >= m_nCols))
    {
      throw new MatrixException (MatrixException.INVALID_INDEX);
    }

    final ColumnVector cv = new ColumnVector (m_nRows);
    for (int r = 0; r < m_nRows; ++r)
    {
      cv.m_aValues[r][0] = m_aValues[r][c];
    }

    return cv;
  }
Get a column of this matrix.

@param c
the column index
@return the column as a column vector
@throws MatrixException
for an invalid index