Name

isdef — checks variable existence

Calling Sequence

isdef(name [,where])

Parameters

name

a character string

where

an optional character string with default value 'all'

Description

isdef(name) returns %T if the variable namedname exists and %F otherwise.

Caveats: a function which uses isdef may return a result which depends on the environment!

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

isdef(name,'nolocal') returns %T if the variable named name exists in the full calling environment (including the global level) of the current function and %F otherwise.

Examples

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

function level1()
  function level2()
    disp(isdef("a","all"));
    disp(isdef("a","local"));
    disp(isdef("a","nolocal"));
  endfunction
  level2()
endfunction
function go()
  a=1;
  level1()
endfunction
go()
   

See Also

exists isglobal, whereis, type, typeof, clear