MATLAB: Counting duplicate cells in a matrix

Question

Hello everyone,

Suppose matrix a is like:

a = [12,28,28,32,32,37,48,72,72,73,73,73,97,100,100,100];

I want matrix b to be like:

b = [1,2,2,3,3,4,5,6,6,7,7,7,8,9,9,9]

Matrix b is repeating duplicate cells in the matrix a

For example:

1 = 12 (repeat, 1)
2 = 28 (repeat, 2)
3 = 32 (repeat, 2)
.
.
.
7 = 73 (repeat, 3)

Can anyone please help me?

Answer 1

help unique

Look at the latter arguments. For example, try this:

[~,~,b] = unique(a);