MATLAB: Combining two arrays question

Question

Hello. I have a structure array 'data', and I am trying to define a new variable called 'loc'. The problem I am encountering is that I want to get for example, when I write something like loc(1) in the command window, I get [data(1).Lat data(1).Lng].

The following is the code I am using.

 for n = 1 : length(data)
  if ~isempty(data(n).Lat & data(n).Lng)
  loc(n) = [data(n).Lat data(n).Lng];
  end
  end

I have just started using Matlab and will greatly appreciate your help. Thanks in advance.

Answer 1

You should learn to program without trying on loops for everything: this will be faster and neater code in MATLAB, and is called vectorization. In this case there is no need for any loops or arrayfun calls, just use MATLAB's inbuilt structure accessing syntax:

>> A(3).lat = 1.3;
>> A(3).lng = 0.3;
>> A(2).lat = 1.2;
>> A(2).lng = 0.2;
>> A(1).lat = 1.1;
>> A(1).lng = 0.1;
>> [[A.lat]',[A.lng]']
ans =
          1.1          0.1
          1.2          0.2
          1.3          0.3

Read more here:

http://www.mathworks.com/help/matlab/matlab_prog/access-multiple-elements-of-a-nonscalar-struct-array.html

http://www.mathworks.com/help/matlab/matlab_prog/access-data-in-a-structure-array.html