Sorting group position from 1

I have a group number of array

1) [2 3 2 1] I want [1 2 1 3]

2) [3 3 1 2] I want [1 1 2 3]

Answer 1

[Jonas]

i think you are searching for this:

[~,~,c]=unique([2 3 2 1],'stable')

c = 4×1

1 2 1 3

[~,~,c]=unique([3 3 1 2],'stable')

c = 4×1

1 1 2 3