Accesing a field within a row of a data structure

I have the following code

A=[DS.Carb]>2700;
B=[DS.Vit]==1;
C=or(A,B);
Index=find(C==1);
M=[DS.User_ID(Index)];

As you can see I am trying to acces some parts of the datastructure DS and save some information deending on "Index"

for exaple if Index=[3 4 67 8] then I would like to extract the content of the User_ID corresponding to the index each time

Answer 1

[Voss]

The correct syntax for getting the User_ID of elements at indices Index of struct array DS would be

M = [DS(Index).User_ID];

or

M = {DS(Index).User_ID};

depending on the class of the data stored in field User_ID.

For example:

DS = struct( ...
    'User_ID',{1 2 3 4}, ...
    'Carb',{2600 2800 2600 2800}, ...
    'Vit',{0 0 1 1});

M = [DS([DS.Carb]>2700 | [DS.Vit]==1).User_ID]

M = 1×3

2 3 4

DS = struct( ...
    'User_ID',{'one' 'two' 'three' 'four'}, ...
    'Carb',{2600 2800 2600 2800}, ...
    'Vit',{0 0 1 1});

M = {DS([DS.Carb]>2700 | [DS.Vit]==1).User_ID}

M = 1×3 cell array
    {'two'}    {'three'}    {'four'}

[Mehdi Jaiem]

Thank you very much ! Both worked yes.