Once a data set has been read, there is a window based facility in . for making small changes. The command
xnew <- data.entry(xold)
will allow you to edit your data set xold using a spreadsheet-like environment in a separate editing window, and on completion the changed object is assigned to xnew. xold, and hence xnew, can be any matrix, vector, data frame, or atomic data object.
Calling data.entry() with no arguments,
xnew <- data.entry()
lets you enter new data via the spreadsheet interface.