st: Manipulating dataset in stata

[Cesare Fracassi <cesare.fracassi.2009@anderson.ucla.edu>]

Hi All,

I have a db that looks like this:

ID   N
1      1
2      0
3      4
4      2
5      2
6      0
.........
10     1


(the actual db is much larger than that)

I would like to create a new dataset that contains the nxn possible 
combinations of observations and takes the differences between the Ns:

ID1   ID2   DeltaN
1         1          0 
1        2          1
1        3         -3
1        4         -1
........................
1      10         0
2         1         -1
2         2         0
2          3         -4
.......

and so on for the nxn possible combinations...

any idea how to code that in stata?

thanks in advance...

Cesare










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