isdef

Arguments

ve

a matrix with the same size as name with boolean values

name

a matrix of character strings

where

character string, can be 'l' (for "local"), 'n' (for "nolocal") or 'a' (for "all"). Default value is 'a'.

Description

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

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

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

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

Note: only the first letter of option where is taken into account.

Examples

A = 1; B = 2; C = 3; D = 4;
isdef(['A', 'B'; 'C', 'D'])
clear A B C D;
isdef(['A', 'B'; 'C', 'D'])

function level1()
  function level2()
    disp(isdef(["a", "b"], "a"));
    disp(isdef(["a", "b"], "l"));
    disp(isdef(["a", "b"], "n"));
  endfunction
  level2()
endfunction
function go()
  a = 1;
  level1()
endfunction
go()

See also

• exists — checks variable existence
• isglobal — check if a variable is global
• whereis — name of library containing a function
• type — returns the type of a variable
• typeof — explicit type or overloading code of an object
• clear — kills variables