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st: AW: loop question


From   "Martin Weiss" <martin.weiss1@gmx.de>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: AW: loop question
Date   Mon, 2 Nov 2009 22:47:01 +0100

<> 


*************
clear*

inp byte(group_id member_id) C 
1 1  300  
1 2  200  
1 3  100  
2 1  150  
2 2  200  
2 3  100  
2 4  50   
end

compress
l, noo sepby(group_id)

bys group_id (C):  /* 
*/ gen diff=C[_n+1]-C[_n]
bys group_id: gen num=_N-_n
bys  group_id (num): /* 
*/ gen outcome_var=sum(diff*num)
sort group_id member_id

drop diff num
l, noo sepby(group_id)
*************


HTH
Martin

-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Sandu Cojocaru
Gesendet: Montag, 2. November 2009 20:35
An: statalist@hsphsun2.harvard.edu
Betreff: st: loop question

Dear All:

I'm having trouble generating a variable that for each member i equals
sum(Cj-Ci) over all Cj>Ci where i and j are members of the same group.
Here's an example of the data setup - I'm trying to calculate
`outcome_var'.
For row 1 outcome_var=0, for row 3 = (200-100)+(300-100) = 300...and so
on...

group_id       member_id       C           outcome_var
1                  1                     300        0
1                  2                     200        100
1                  3                     100        300
2                  1                     150        50
2                  2                     200        0
2                  3                     100        150
2                  4                     50          300
3                  1 and so on...

Any help would be greatly appreciated!
sandu
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