How to choose value from array based on closest value

Question

Alex 2022-7-13

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https://ww2.mathworks.cn/matlabcentral/answers/1759195-how-to-choose-value-from-array-based-on-closest-value

回答： Ruchika P Barman 2022-7-13

I have a 41x2 array. I want to take an input variable, find the closest value in the first column, and assign the corresponding value in the second column to a new variable.

Any pointers on how I would go about doing this?

For example:

Input value is x = 3.2
Search first column in array for 3.2
Closest value is 3
Value in 2nd column corresponding to 3 is 500
Store 500 to new variable y

Thanks!

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Answer 1

Walter Roberson 2022-7-13

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If the values in the first column are sorted, use interp1() with 'nearest'

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Alex 2022-7-13

This worked perfectly, thanks!

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Answer 2

Ruchika P Barman 2022-7-13

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在 MATLAB Online 中打开

It is my understanding that you are trying to get the element closest to the input number by comparing with all the elements in the matrix column-wise. The following code should be able to achieve the same.

V=[0.87]
V = 0.8700
arr = rand(41,2)
arr = 41×2
    0.0928    0.4712
    0.5737    0.6716
    0.0275    0.0357
    0.3457    0.5579
    0.6198    0.3686
    0.1062    0.9167
    0.5590    0.4408
    0.1859    0.6384
    0.8755    0.7567
    0.3914    0.0726
 
for c=1:2
    N=arr(:,c);
    A = repmat(N,[1 length(V)]);
    [minValue,closestIndex] = min(abs(A-V'));
    closestValue = N(closestIndex);
    V=closestValue;
end
V
V = 0.8895