Find closest value in array

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Chiranjibi ，2014-8-25

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https://ww2.mathworks.cn/matlabcentral/answers/152301-find-closest-value-in-array

评论： Adrian Aquino Arriaga ，2021-10-8

I have two vector(which are time stamps) like,

           V                                    N
     1375471092848936                   1375473384440853
     1375473388165900                   1375471277856598
     1375471320476780                   1375473388165900
     1375473388947681                   1375471322465961
     1375473392527002                   1375471335206288
    ..................                  ..................

My goal is to find closest time in N with respect to V (i.e. find time in N which is nearly equal with V). My frame is W = 1e4, furthermore V should lies between N-W and N+W. So how do I get closest time through MATLAB? Any help would be appreciated.

Thanks

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Answer 1

Joe S 2018-9-10

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https://ww2.mathworks.cn/matlabcentral/answers/152301-find-closest-value-in-array#answer_336210

编辑：MathWorks Support Team 2018-11-27

To compute the closest value in a vector “N” for each element of “V”, try the following code with example vectors “N” and “V”:

V = randi(10,[5 1])
N = randi(10,[5 1])
 
A = repmat(N,[1 length(V)])
[minValue,closestIndex] = min(abs(A-V’))
closestValue = N(closestIndex) 

Note that if there is a tie for the minimum value in each column, MATLAB chooses the first element in the column.

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Adrian Aquino Arriaga 2021-10-8

Great answer. I would only use dot-apostrophe (.') instead of only apostrophe to make sure you are taking the non-conjugate transpose. Of course, this is only relevant if you are working with complex numbers.

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Answer 2

Andrew Reibold 2014-8-25

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编辑：Andrew Reibold 2014-8-25

This finds the value in N which is closest to the V value I am calling.

N = [1990 1998 2001 2004 2001]
V = [2000 2011 2010 2001 1998]
[c index] = min(abs(N-V(1)))

In this case Im looking for the closest value to 'V(1)' which is 2000. It should return the 3rd or 5th value of N which is 2001.

Note: 'index' is the index of the closest value. If two are the same, like in this example with two different '2001's, it will return the index of the first one.

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Image Analyst 2018-2-17

reetu, if N is just a single number then you can do this

[minDistance, indexOfMin] = min(abs(V-N));

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Answer 3

Image Analyst 2014-8-25

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https://ww2.mathworks.cn/matlabcentral/answers/152301-find-closest-value-in-array#answer_149791

How about this:

clc;
% Sample data
numberOfRows = 5;
V = rand(numberOfRows, 1)
N = rand(numberOfRows, 1)
% Find min distance
minDistance = inf;
for ni = 1 : numberOfRows
  for vi = 1 : numberOfRows
    distances(vi, ni) = abs(N(ni) - V(vi));
    if distances(vi, ni) < minDistance
      minNRow = ni;
      minVRow = vi;
      minDistance = distances(vi, ni);
    end
  end
end
% Report to command window:
distances
fprintf('Closest distance is %f which occurs between row %d of N and row %d of V\n',...
  minDistance, minNRow, minVRow);

In the command window:

V =
5309
6544
4076
8200
7184
N =
9686
5313
3251
1056
6110
distances =
4378    0.0005    0.2057    0.4252    0.0801
3142    0.1231    0.3293    0.5488    0.0435
5610    0.1237    0.0825    0.3020    0.2033
1487    0.2886    0.4948    0.7144    0.2090
2503    0.1870    0.3932    0.6127    0.1074
Closest distance is 0.000470 which occurs between row 2 of N and row 1 of V