MATLAB: Give number to sequence

Question

I have sequence

a=[17 56 42 12 12 99 102 45 76 76 41 99 12 45 56 17 76 86 125 160 36]

I want to do that give numbering to sequence starting from 1 i.e.minimum value is 12 so give it 1 then next value greater than 12 is 17 so give it 2 likewise so

a  = [17 56 42 12 12 99 102 45 76 76 41 99 12 45 56 17 76 86 125 160 36]
a1 = [2  7  5  1  1 10  11  6  8  8  4  10 1  5  7  2  8   9  12 13  3]

how to do this.

Answer 1

Here's one semi-vectorized way:

a=[17 56 42 12 12 99 102 45 76 76 41 99 12 45 56 17 76 86 125 160 36]
uniquea = unique(a)
labels = 1 : length(uniquea)
for k = 1 : length(a)
  index = find(a(k) == uniquea);
  a1(k) = labels(index);
end