# Find all unique values and replace it with new values

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Elysi Cochin on 6 Jun 2022
Commented: Image Analyst on 7 Jun 2022
I have a vector with values
v = [0.23; 0.1; 0.33; 0.23 ; 0.33; 0.6; 0.6; 0.4];
I would like to find the unique values and replace the vector with numbers from 1, like
newV = [1; 2; 3; 1 ; 3; 4; 4; 5];

Walter Roberson on 6 Jun 2022
findgroups()
But since you are using floating point numbers you really should use the third output of uniquetol() instead
Elysi Cochin on 7 Jun 2022
okay sir will consider that
Image Analyst on 7 Jun 2022
@Elysi Cochin I'm pretty sure you've seen the FAQ on this before but here it is again:

### More Answers (2)

KSSV on 6 Jun 2022
v = [0.23; 0.1; 0.33; 0.23 ; 0.33; 0.6; 0.6; 0.4];
[c,ia,newV] = unique(v,'stable') ;
newV
newV = 8×1
1 2 3 1 3 4 4 5

Image Analyst on 6 Jun 2022
Will this do:
v = [0.23; 0.1; 0.33; 0.23 ; 0.33; 0.6; 0.6; 0.4];
% newV = [1; 2; 3; 1 ; 3; 4; 4; 5];
[g, Tid] = findgroups(v)
g = 8×1
2 1 3 2 3 5 5 4
Tid = 5×1
0.1000 0.2300 0.3300 0.4000 0.6000
I know it doesn't match your desired but it's easy and maybe you don't need that exact order. If you need that exact order, can you explain why you need that order? (And don't jsut say I need it because I need it.)
Elysi Cochin on 6 Jun 2022
Order not important