MATLAB: How to extract rows has a same value in column 1 and plot until those rows of column 2 and 3

Question

Hi everyone, I have a matrix with repeated values in the 1st column, for example:

 A = [
 1  15  43;
 2  05  64;
 2  13  32;
 3  11  35;
 3  01  20;
 3 -15  08;
 4  46  742;
 4  25  234;
 ..........;]--- let say, there are 2500 rows and repetition values are 2000.

Using A, I am looking to extract data from the 2nd and 3rd column for each value in the 1st column to output B and plot it. Where repetition occurs for a value in the 1st column, the corresponding values in the 2nd and 3rd column are to be plotted (that means 2000 graphs). until end of rows.

I have attempted to use a combination of find functions, if statements and loops, but without success. Ideally, a successful approach would also be efficient, as the actual dataset is large.

Answer 1

You can create a cell array of the separated element as

unique_element = unique(A(:,1));
seperate = cell(numel(unique_element), 1);
for i=1:numel(unique_element)
    index = A(:,1)==unique_element(i);
    seperate{i} = A(index, 2:3);
end

The separated values are stored in variable seperate which is a cell array. You can access its values as seperate{1}, seperate{2}, ... or loop through the entire array using for loop and do whatever manipulation or visualization you want on them.