give number to sequence

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

[Image Analyst]

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

[Jay Hanuman]

but i don't want to disturb original sequence so in original sequence way numbering should be display. in above solution original sequence displays in increasing order numbers.

[Image Analyst]

My code gives

a1 =
  Columns 1 through 17
     2     7     5     1     1    10    11     6     8     8     4    10     1     6     7     2     8
  Columns 18 through 21
     9    12    13     3

Tell me which elements are not in the same order as the a1 you gave, which is a1 = [2 7 5 1 1 10 11 6 8 8 4 10 1 5 7 2 8 9 12 13 3]

I'm just not seeing any difference between my output and yours so I need you to point it out to me. Which indexes are bad?

[Jay Hanuman]

sorry, it gives right result, I didn't saw clearly, Thank You.