CLEAR CLEAR Clear or Delete a Variable

Usage

Clears a set of variables from the current context, or alternately, 
delete all variables defined in the current context.  There are
several formats for the function call.  The first is the explicit form
in which a list of variables are provided:

   clear a1 a2 ...

The variables can be persistent or global, and they will be deleted.
The second form

   clear 'all'

clears all variables and libraries from the current context.  Alternately, you can
use the form:

   clear 'libs'

which will unload any libraries or DLLs that have been imported. 
Optionally, you can specify that persistent variables should be cleared via:

   clear 'persistent'

and similarly for global variables:

   clear 'global'

You can use

   clear 'classes'

to clear all definitions of user-defined classes.
With no arguments, clear defaults to clearing 'all'.
