isdef

isdef — check variable existence

Calling sequence

isdef(name [,where])

`name`	: a character string
`where`	: an optional character string with default value 'all'

isdef(name) returns %T if the variable 'var-name' exists and %F otherwise.

isdef(name,'local') returns %T if the variable 'var-name' exists in the local environment of the current function and %F otherwise.



A=1;
isdef('A')
clear A
isdef('A')