Construct a new structure r' from a first one r by adding new elements.

Hy,

I have a code which gives a structure r (like shown below) and I want to add values D_1 to D_6 "given as data" to construct a new structure r' shown also below as an example.

Can you tell me how to do this please?

r =

struct with fields:

    D_1_2: 1.9202e+03
    D_1_3: 3.4417e+03
    D_1_4: 1.9331e+03
    D_1_5: 1.8763e+03
    D_1_6: 1.1525e+03
    D_2_3: 3.4421e+03
    D_2_4: 1.9335e+03
    D_2_5: 1.8986e+03
    D_2_6: 1.2044e+03
    D_3_4: 3.4898e+03
    D_3_5: 101.9928
    D_3_6: 3.4193e+03
    D_4_5: 1.8928e+03
    D_4_6: 1.1630e+03
    D_5_6: 1.1600e+03

r' =

struct with fields:

    D_1: valeur 
    D_2: valeur
    D_3: valeur
    D_4:valeur 
    D_5:valeur
    D_6:valeur
    D_1_2: 1.9202e+03
    D_1_3: 3.4417e+03
    D_1_4: 1.9331e+03
    D_1_5: 1.8763e+03
    D_1_6: 1.1525e+03
    D_2_3: 3.4421e+03
    D_2_4: 1.9335e+03
    D_2_5: 1.8986e+03
    D_2_6: 1.2044e+03
    D_3_4: 3.4898e+03
    D_3_5: 101.9928
    D_3_6: 3.4193e+03
    D_4_5: 1.8928e+03
    D_4_6: 1.1630e+03
    D_5_6: 1.1600e+03

Answer 1

[Steven Lord]

rprime = r;
rprime.D_1 = 42;
% etc.

If you had a cell array containing the names of the fields you want to add to rprime along with a data array of the same size, use dynamic field names.

fieldsToAdd = {'apple', 'banana', 'coconut'};
dataToAdd = [5, 6, 7];
for k = 1:length(fieldsToAdd)
  thefield = fieldsToAdd{k};
  thedata = dataToAdd(k);
  rprime.(thefield) = thedata;
end

Note I used curly braces to retrieve the field name but parentheses to retrieve the field data, since the data was stored in a numeric vector. If your data was a different size for each field, you would also need to store it in a cell array and use curly brace indexing to extract it from the cell.