checks variable existence
ve = exists(name [,where])
a matrix with the same size as name
with possible values:
1
if true,
0
if false
a matrix of character strings
an optional character with possible values:
'l'
(local), 'n'
(nolocal) and 'a'
(all). The default
value is 'a'
.
exists(name)
returns 1
if the
variable named name
exists and 0
otherwise.
Caveats: a function which uses exists
may return
a result which depends on the environment!
exists(name,'l')
returns 1
if the variable named name
exists in the environment of
the current function and 0
otherwise.
exists(name,'n')
returns
1
if the variable named name
exists
in any level of the calling environment (including the Scilab shell main level) of the current function and
0
otherwise.
![]() | Warning: the exists function does not check if a variable exists in
the global namespace. |
deff('foo(x)',.. ['disp([exists(''a12''),exists(''a12'',''l'')])' 'disp([exists(''x''),exists(''x'',''l'')])']) foo(1) a12=[];foo(1) function level1() function level2() disp(exists(["a","b"],"a")); disp(exists(["a","b"],"l")); disp(exists(["a","b"],"n")); endfunction level2() endfunction function go() a=1; level1() endfunction go() | ![]() | ![]() |