How to find the minimum number in matrix among the repeated array

Martix A is as follows:

A = [36  2  896  965
36  2  965  1354
36  4  1354  1400
36  3  1400  1450
36  2  1450  1700
36  2  1700  1800
36  5  1800  1850
88  2  30  45
88  2  45  110
88  4  110  560
11  5  66  73
11  3  73  90
];

I want to form a new matrix B such as:

B = [36  2  896  458
36  4  1354  46
36  3  1400  50
36  2  1450  350
36  5  1800  50
88  2  30  80
88  4  110  450
11  5  66  7
11  3  73  17
];

First and second column on matrix B: It found each unique ID (first column) according to the unique array of the second column Third column: minimum corresponded array from unique third columns of matrix A Fourth column: is the difference between two value of the fourth column from matrix A of two similar arrays of the second row

For example:

% 458 = 1354 - 896
% 46 = 1450 - 13545
% 50 = 1450 - 1400
% 350 = 1800 - 1450

[Alex Rob]

I wrote this code:

B = grpstats(A, A(:, 1:2), 'min')

But, somehow it works based on the only unique value of column 2

Any thought or help?

Answer 1

[Stephen23]

This will give you the first three columns:

A = [...
    36,2,896,965
    36,2,965,1354
    36,4,1354,1400
    36,3,1400,1450
    36,2,1450,1700
    36,2,1700,1800
    36,5,1800,1850
    88,2,30,45
    88,2,45,110
    88,4,110,560
    11,5,66,73
    11,3,73,90
];
[~,idx,idy] = unique(A(:,1:2),'rows','stable');
B = A(idx,:)
B(:,3) = accumarray(idy,A(:,3),[],@min)

But I really have no idea what you want for the fourth column. What does "the difference between two value of the fourth column from matrix A of two similar arrays of the second row" mean ? What are similar rows ? Why these numbers?

 458 = 1354 - 896
 46 = 1450 - 13545

13545 is not in your array A: how did you get this value?