Collapsing integer data into consecutive integers?

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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!
  3 Commenti
John
John il 18 Giu 2013
It looks like you just divided everything by 2, rounding up.
Mark
Mark il 18 Giu 2013
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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Risposta accettata

Tom
Tom il 18 Giu 2013
[~,~,I] = unique([ 0 1 4 4 1 5 8 1 4]);
disp(I-1)

Più risposte (1)

Iain
Iain il 18 Giu 2013
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;

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