Collapsing integer data into consecutive integers?

Question

Mark 2013-6-18

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/79414-collapsing-integer-data-into-consecutive-integers

I have a matrix of values that include integers >= 0. There are repeats, and also gaps in consecutiveness. I would like to collapse the data into consecutive integers, keeping the order intact.

Example: [ 0 1 4 4 1 5 8 1 4]

would go to

[ 0 1 2 2 1 3 4 1 2]

I can do this with loops and brute force, but I'm wondering if there's any quick way to do this since it is frequently called within a loop?

Thanks!

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John 2013-6-18

It looks like you just divided everything by 2, rounding up.

Mark 2013-6-18

Not consecutive in the array, but consecutive in the counting of unique numbers in the original. I.e., there are 5 unique numbers in the original vector, 0 1 4 5 and 8. I wanted to map those to 0 1 2 3 4. (The divide by two and round was just coincidence!) The problem has been solved below. Thanks.

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Answer 1

Tom 2013-6-18

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https://ww2.mathworks.cn/matlabcentral/answers/79414-collapsing-integer-data-into-consecutive-integers#answer_89167

在 MATLAB Online 中打开

[~,~,I] = unique([ 0 1 4 4 1 5 8 1 4]);
disp(I-1)

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Answer 2

Iain 2013-6-18

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/79414-collapsing-integer-data-into-consecutive-integers#answer_89166

在 MATLAB Online 中打开

 Ex = [ 0 1 4 4 1 5 8 1 4]; % A row
 V = unique(Ex); % should be a row 
 L = bsxfun(@eq,Ex,V); 
 Collapsed = [0:(numel(V)-1)]*L;
 Reconstructed = V' * L;