Find index of a nearest value

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

Answer 1

[Matlab Pro]

Hi @Adi Purwandana

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

<mw-icon class=""></mw-icon>

<mw-icon class=""></mw-icon>

[Adi Purwandana]

thank you @Matlab Pro!

Answer 2

[Image Analyst]

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

Answer 3

[Voss]

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

<mw-icon class=""></mw-icon>

<mw-icon class=""></mw-icon>

closest = x(idx)

closest = 1x9

11 21 51 100 151 201 251 301 401

<mw-icon class=""></mw-icon>

<mw-icon class=""></mw-icon>

Answer 4

[Pratyush]

Hi Adi,

The following script should help you find the indices of values closest to given numbers in an array.

% Your data
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]

thank you @Pratyush