how to take a matrix of certain values taken from the matrix

hello guys,

I am a beginner in using matlab, and I have a case which I can't solve it, can anyone help?

I have a 7 x 2 input matrix, as I demonstrated below

A = [1 100
       2 110
       3 120
       4 130
       5 140
       6 150
       7 160]

and then i have a value of 125. from that value i want i get a new matrix that is

B = [3 120
      4 130]

Could someone help me please?

dzulakbar

Answer 1

[Walter Roberson]

q = 125;
idx = interp1(A(:,2), (1:size(A,1)).', q);
B = A(floor(idx):ceil(idx), :);

This relies upon the entries in the second column being monotonic (all increasing or all decreasing.)

[Muhammad Dzul Akbar]

thanks walter :)

[madhan ravi]

If the code is working you can thank the person by accepting their answer.

[Muhammad Dzul Akbar]

okey ravi

Answer 2

[Andrei Bobrov]

q = 125;
[~,inx] = mink(abs(A(:,2) - q),2);
B = A(inx,:);

or for old MATLAB

q = 125;
[~,inx] = sort(abs(A(:,2) - 125));
B = A(inx(1:2),:);

[Muhammad Dzul Akbar]

thanks andrei