getcolnames
==============================================

Purpose
----------------

Returns the column variable names.

Format
----------------
.. function:: varnames = getColNames(X [, columns])

    :param X: data with metadata.
    :type X: NxK dataframe.

    :param columns: Optional argument, the indices of the columns in *X* to get variable names of. Default = all columns.
    :type columns: Kx1 vector

    :return varnames: Variable names in matrix *X* for the columns specified by *columns*.
    :rtype varnames: Kx1 string array


Examples
----------------

::

  // Load data
  fname = getGAUSSHome("examples/yarn.xlsx");
  yarn = loadd(fname, "cat(yarn_length) + cat(amplitude) + cat(load) + cycles");

  // Get column names for first and second
  // column in yarn
  getColNames(yarn, 1|2);

The code above prints the following:

::

  yarn_length
  amplitude

.. seealso:: Functions :func:`dfname`