When Select( is called, if it has any Scatter or xyLine plots to work with, it displays the graph screen and allows the user to pick a left bound and then a right bound on one of the plots (the left and right keys move from point to point, while the up and down keys switch plots). Then, it stores all the points between those bounds to x-list name and y-list name. Finally, it sets the chosen plot to use x-list name and y-list name as its X and Y lists.
It isn't necessary to add the ∟ symbol before list names:
:Select(∟X,∟Y) can be :Select(X,Y)
- ERR:INVALID is thrown if there are no enabled Scatter or xyLine plots for the command to work with.