public MultiGetterAt <MutableTuple <T1> > GetMultiGetterAt <T1>(int[] cols)
where T1 : IEquatable <T1>, IComparable <T1>
{
var newCols = _columns == null ? cols : cols.Select(c => _columns[c]).ToArray();
return(_src.GetMultiGetterAt <T1>(newCols));
}
public DataFrame TJoin <T1, T2, T3>(IDataFrameView right, IEnumerable <int> colsLeft, IEnumerable <int> colsRight, string leftSuffix = null, string rightSuffix = null, JoinStrategy joinType = JoinStrategy.Inner, bool sort = true)
where T1 : IEquatable <T1>, IComparable <T1>
where T2 : IEquatable <T2>, IComparable <T2>
where T3 : IEquatable <T3>, IComparable <T3>
{
int[] orderLeft = _rows.Select(c => c).ToArray();
int[] orderRight = (right as DataFrame) is null ? (right as DataFrameView)._rows.Select(c => c).ToArray() : null;
int[] columnsRight = (right as DataFrame) is null ? (right as DataFrameView)._columns : null;
var icolsLeft = colsLeft.ToArray();
var icolsRight = colsRight.ToArray();
var scolsLeft = icolsLeft.Select(c => Schema.GetColumnName(c)).ToArray();
var scolsRight = icolsRight.Select(c => right.SchemaI.GetColumnName(c)).ToArray();
return(DataFrameJoining.TJoin(this, right,
orderLeft, orderRight,
_columns, columnsRight,
icolsLeft, icolsRight, sort,
leftSuffix, rightSuffix,
joinType,
GetMultiGetterAt <T1, T2, T3>(icolsLeft),
right.GetMultiGetterAt <T1, T2, T3>(icolsRight),
ke => ke.ToImTuple(),
ke => DataFrameGroupKey.Create(scolsLeft, ke),
ke => DataFrameGroupKey.Create(scolsRight, ke)));
}