Data Permanency. Removing Objects.

The entities that . creates and manipulates are known as objects. These may be variables, arrays of numbers, character strings, functions, or more general structures built from such components.

During an . session, objects are created and stored by name (we discuss this process in the next session). The . command

objects()

can be used to display the names of the objects which are currently stored within ..

To remove objects the function rm is available:

rm(x, y, z, ink, junk, temp, foo, bar)

All objects created during an . sessions can be stored permanently in a file for use in future . sessions. At the end of each . session you are given the opportunity to save all the currently available objects. If you indicate that you want to do this, the objects are written to a file called .RData. in the current directory.

When . is started at later time it reloads the objects from this file (at the same time the associated command history is also reloaded under Unix).

It is recommended that you should use separate working directories for analyses conducted with .. It is quite common for objects with names x and y to be created during an analysis. Names like this are often meaningful in the context of a single analysis, but it can be quite hard to decide what they might be when the several analyses have been conducted in the same directory.