datatable.join()

Join clause for use in Frame’s square-bracket selector.

This clause is equivalent to the SQL JOIN, though for the moment datatable only supports left outer joins. In order to join, the frame must be keyed first, and then joined to another frame DT as

DT[:, :, join(X)]

provided that DT has the column(s) with the same name(s) as the key in frame.

Parameters

frame
Frame

An input keyed frame to be joined to the current one.

return
Join Object

In most of the cases the returned object is directly used in the Frame’s square-bracket selector.

except
TypeError

The exception is raised if the input frame is missing.

except
ValueError

The exception is raised if frame is not keyed.