Is it possible to check for existence of fields in nested structures with isfield in MATLAB 8.1 (R2013a)?

I have the following structure

a.b.c = 1;

I know it is possible to search for the nested

isfield(a.b,'c')

But I would like to check for the existence of the field 'c' even when I am not sure that the field 'b' exists, e.g.

isfield(a,'b.c');

Answer 1

[MathWorks Support Team]

There is no MATLAB function to determine the existence of fields in nested structures. The only workaround is to check separately for the existence of 'b' and of 'c':

isfield(a, 'b') && isfield(a.b, 'c')

Answer 2

[Steven Lord]

Another approach that uses neither eval nor repeated calls to isfield is to use getfield.

a.b.c = 1;
isNestedField(a, 'b.c')

ans = logical
   1

isNestedField(a, 'b.d')

ans = logical
   0

isNestedField(1:10, 'a')

ans = logical
   0

function tf = isNestedField(s, thefields)
fieldlist = split(thefields, '.');
try
    getfield(s, fieldlist{:});
    tf = true;
catch
    tf = false;
end
end