# Find index of a nearest value

8 views (last 30 days)
Adi Purwandana on 17 Jun 2024
Answered: Voss on 17 Jun 2024
Hello there,
If I have a data: x = [1 2 3 4 5 6 11 15 21 51 52 54 100 101 151 201 251 301 401];
Anyone knows how to get the index of the value close to a certain values: 10, 20, 50, 100, 150, 200, 250, 300, 400?
In this case, the index should be related to the x = 11, 21, etc.
thanks

Matlab Pro on 17 Jun 2024
A simple slution using dsearchn
x = [1 2 3 4 5 6 11 15 21 51 52 54 100 101 151 201 251 301 401];
vals = [10, 20, 50, 100, 150, 200];
dsearchn(x(:),vals(:))
ans = 6x1
7 9 10 13 15 16
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Adi Purwandana on 17 Jun 2024
thank you @Matlab Pro!

Image Analyst on 17 Jun 2024
Another solution
x = [1 2 3 4 5 6 11 15 21 51 52 54 100 101 151 201 251 301 401];
targetValue = 10;
[~, index] = min(abs(x - targetValue))
index = 7
closestValue = x(index)
closestValue = 11

Voss on 17 Jun 2024
x = [1 2 3 4 5 6 11 15 21 51 52 54 100 101 151 201 251 301 401];
target = [10, 20, 50, 100, 150, 200, 250, 300, 400];
[~,idx] = min(abs(x(:)-target(:).'),[],1)
idx = 1x9
7 9 10 13 15 16 17 18 19
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closest = x(idx)
closest = 1x9
11 21 51 100 151 201 251 301 401
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Pratyush on 17 Jun 2024
The following script should help you find the indices of values closest to given numbers in an array.
x = [1 2 3 4 5 6 11 15 21 51 52 54 100 101 151 201 251 301 401];
% The target values you want to find the closest in x
targets = [10, 20, 50, 100, 150, 200, 250, 300, 400];
% Preallocate the array for indices
indices = zeros(size(targets));
% Loop through each target value
for i = 1:length(targets)
% Calculate the absolute differences
[~, indices(i)] = min(abs(x - targets(i)));
end
% Display the indices
disp(indices);
Adi Purwandana on 17 Jun 2024
thank you @Pratyush

R2022a

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