MATLAB: Sorting 2D matrix

sort

Hello all,

I'm troubling with sorting of the matrix. I have a matrix

A  =   6.0000   18.0000   20.0000   23.0000   26.0000
       3.1464    1.4302    2.9512    0.9988    2.7403

I need to sort the second row in ascending order. Simultaneously the first row also needs to be sorted according to the second row like

required matrix = 23.0000  18.0000  26.0000 20.0000 6.0000
                  0.9988   1.4302   2.7403  2.9512  3.1464

when I trying to use the sort command like sort(A,2), I'm getting

sort(A,2)= 
      6.0000   18.0000   20.0000   23.0000   26.0000
      0.9988    1.4302    2.7403    2.9512    3.1464

Can you help me here. Thank you.

Best Answer

>> sortrows(A.',2).'
ans =
 23.0000   18.0000   26.0000   20.0000    6.0000
  0.9988    1.4302    2.7403    2.9512    3.1464
>>

Related Solutions

MATLAB: Eliminate rows in a matrix that have matching & different values

Assuming your matrix is A, the following code returns what you want as B.

B = sortrows(A,[1 4]);
idx = [false; diff(B(:,1)) == 0];
B(idx,:) = [];

MATLAB: How do cumulatively add a matrix column based on a vector

Try this:

t = [...
  1.0000    7.0000         0         0
  2.0000    9.0000    0.6000    3.0000
  3.0000   11.0000   -0.5000   -0.5000
  4.0000   13.0000    0.6000    2.4000
  5.0000   14.0000   -0.7000   -2.5000
  6.0000   18.0000    0.7000    2.4000
  7.0000   19.0000   -0.2000    1.0000
  8.0000   20.0000         0    1.0000
  9.0000   22.0000    0.7000    2.1000
  10.0000   23.0000   -0.1000    1.4000
  11.0000   24.0000         0    1.4000
  12.0000   25.0000    0.2000    0.4000
  13.0000   26.0000         0    0.4000
  14.0000   28.0000    0.5000    0.5000
  15.0000   29.0000   -0.2000   -0.9000
  16.0000   30.0000    0.2000    0.5000
  17.0000   31.0000   -0.1000   -0.2000
  18.0000   32.0000    0.3000         0
  19.0000   33.0000   -0.3000   -2.1000
  20.0000   34.0000    0.2000   -0.7000
  21.0000   35.0000   -0.1000   -1.4000
  22.0000   39.0000         0   -1.4000
  23.0000   42.0000   -0.3000   -3.5000
  24.0000   44.0000    0.3000   -1.4000
  25.0000   45.0000   -0.2000   -2.8000];
% Extract column 1 of t.
column1 = t(:, 1);
% & a vector m, corresponding to column 1 of t, defined as
m = [1 2 4 9 12 14 18];
for k = 1 : length(m) - 1
  index1 = m(k) + 1;
  index2 = m(k + 1) - 1;
  theSum(k) = sum(column1(index1:index2));
  fprintf('Summing column1 from index %d to %d and getting %.1f.\n', index1, index2, theSum(k));
end

You get:

Summing column1 from index 2 to 1 and getting 0.0.
Summing column1 from index 3 to 3 and getting 3.0.
Summing column1 from index 5 to 8 and getting 26.0.
Summing column1 from index 10 to 11 and getting 21.0.
Summing column1 from index 13 to 13 and getting 13.0.
Summing column1 from index 15 to 17 and getting 48.0.

Best Answer

Related Solutions

MATLAB: Eliminate rows in a matrix that have matching & different values

MATLAB: How do cumulatively add a matrix column based on a vector

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