/// <summary>
/// Aggregates over all rows.
/// </summary>
public DataFrame Aggregate(AggregatedFunction agg, int[] rows = null, int[] columns = null)
{
if (rows == null)
{
rows = _rows;
}
else
{
rows = rows.Select(c => _rows[c]).ToArray();
}
if (columns == null)
{
columns = _columns;
}
else
{
columns = columns.Select(c => _columns[c]).ToArray();
}
return(_src.Aggregate(agg, rows, columns));
}