NB.suppose i have a list: z=.5 5 2 20 20 20 60 60 2 2 =z 1 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 1 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 1 1 0 0 NB.how can i generate a list of what will be indices: NB. 0 0 1 2 2 2 3 3 4 4 NB.from original list