Add values to a struct element inside a loop

Hi everyone, I have a vector (B) that contains some values that are repeated and to each value of B corresponds a value of the vector C. For each values of A (from 1 to 5) i want to create a structure element (and store them into a 5x1 cell element) that contains one field (fieldname) with the values of C.

A=[1:5];
B=[1 2 3 4 4 5 4];
C=[10 10 10 10 20 10 30];

for example for the value 1 of A i want a structure 1x1 with field 'fieldname' and value 10 while for the value 4 of A i whant a structure 1x3 with value 10, 20, 30 assigned to the field.

I have tryed this scrip

A=[1:5];
B=[1 2 3 4 4 5 4];
C=[10 10 10 10 20 10 30];
E=cell(length(A),1);
a='fieldname';
for i=1:length(A)
    for r=1:length(B)
        if A(1,i)==B(1,r)
            E{i,1}=struct(a,C(1,r));
        end
    end
end

The problem is that i only obtain 1x1 structure element because the loop overwrites the element in E{i,1} position instead of adding another value to the field. So in position E{4,1} i have a 1x1 struct element with value 30 assigned to the field instead of 1x3 struct with values 10, 20, 30. Someone can help me??

[Jan]

Do you really want a cell array of structs? If all structs have the same field, a struct array would be smarter.

[Federico Selvi]

I don't konow if using the cell array it's the best solution but I'have used it to store the different struct element because i need one of them for each value of the vector A even if they have all the same field. So in this way i want to obtain a 1x1 struct for the value 1, a 1x1 for the value 2 and so on and for the value 4 i need a 1x3 struct

Answer 1

[Jan]

A = 1:5;
B = [1 2 3 4 4 5 4];
C = [10 10 10 10 20 10 30];
E = cell(length(A),1);
a = 'fieldname';
for k = 1:length(A)
   E{k} = struct(a, C(B == A(k)));
end

Maybe this helps:

CellResult   = accumarray(B.', C, [5,1], @(x) {x})
StructResult = cell2struct(CellResult, a, 2)

[Federico Selvi]

thank you, now it's better but the problem remains that the struct element for the value 4 is still a 1x1 (even if it contanis the 3 values 10 20 30). I need it to be a 1x3

[Federico Selvi]

I'have found a solution. I need to write C as a cell element instead of a normal vector.