Reshape data for all values of pid

Question

I have the variables below:

rid     revenue     pid     in_stock
46532   2085405     1013    1
58914   3964121     1021    1

I would like to reshape them as follows:

rid     revenue     pid     in_stock
46532   2085405     1013    1
46532   2085405     1021    0
58914   3964121     1013    0
58914   3964121     1021    1

How can I do this in Stata?

Answer 1

This is too long and too awkward to work well as a comment on @Pearly Spencer's answer. It seems to me that this can be done a little more simply. fillin will do most of the work and there is no need to use save, expand or joinby.

clear 
input rid     revenue     pid     in_stock
46532   2085405     1013    1
58914   3964121     1021    1
end 

fillin rid pid
replace in_stock = 0 if _fillin 
drop _fillin 
bysort rid (revenue) : replace revenue = revenue[1] 
list, sepby(rid) 

     +-----------------------------------+
     |   rid   revenue    pid   in_stock |
     |-----------------------------------|
  1. | 46532   2085405   1013          1 |
  2. | 46532   2085405   1021          0 |
     |-----------------------------------|
  3. | 58914   3964121   1021          1 |
  4. | 58914   3964121   1013          0 |
     +-----------------------------------+