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

MATLAB

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');

Best Answer

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')

Related Solutions

MATLAB: Accessing field names in struct

F = fieldnames(test) ;
F(cell2mat(struct2cell(test)))

MATLAB: Checking if a nested field exists

In your code:

isfield(['A.' D.E.F{i}],'C')

what is D.E.F{i}? A concatenation with 'A.' will create a char vector. Char vectors are no structs, so isfield replies false as expected.

Try this instead:

% Some test data:
A1.B.C         = 1;
A2.AnyStuff    = '?';
A2.FunnyName.C = 2;
A3.HasNoC.D    = 3;
A3.Nonsense    = {};
% TRUE if subfield is existing:
hasSubField(A1, 'C')
hasSubField(A2, 'C')
hasSubField(A3, 'C')
function T = hasSubField(S, F)
T    = false;
Data = struct2cell(S);
for k = 1:numel(Data)
   if isfield(Data{k}, F)
      T = true;
      return;
   end
end
end

This searchs for a subfield in the first level. If any of the fields is a struct and contains the field provided by the input F, true is replied. Or are you searching for deeply nested structs also?

Best Answer

Related Solutions

MATLAB: Accessing field names in struct

MATLAB: Checking if a nested field exists

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