st: reshaping long panel into wide to get rowtotals

[ABDUL ADAM <bihiabdul@yahoo.com>]

Dear Statalist,

I have a panel data with long format  that looks like this:

    +---------------------------------------------------------------------------------+
    |  hhnr      mydate    valc200   valc150    valcrest    tot_val |
    |-----------------------------------------------------------------------------------|
18. | 16414   10jul2006          .          .          .                    0 |
19. | 16414   10jul2006          .   1120.958          .   1120.958 |
20. | 16531   10jul2006          .          .   1199.145   1199.145 |
21. | 16531   10jul2006          .          .          .                    0 |
22. | 16545   10jul2006          .          .   1535.672   1535.672 |
     |-----------------------------------------------------------------------------------|
23. | 16820   10jul2006          .          .   1557.154   1557.154 |
24. | 17222   10jul2006          .          .          .                    0 |
25. | 17432   10jul2006          .          .   2796.389   2796.389 |
26. | 18116   10jul2006          .    3217.72          .    3217.72   |
27. | 18562   10jul2006          .          .    949.102    949.102   |
    |------------------------------------------------------------------------------------|
28. | 18605   10jul2006          .          .   7903.555   7903.555 |
29. | 18753   10jul2006          .    1622.18          .    1622.18 |
30. | 18914   10jul2006          .   7723.083          .   7723.083 |
31. | 18985   10jul2006          .          .   7358.771   7358.771 |
32. | 18985   10jul2006          .   2766.125          .   2766.125 |
    |------------------------------------------------------------------------------------|
33. | 19139   10jul2006          .          .          .                    0 |
34. | 19435   10jul2006          .          .          .                    0 |
35. | 19459   10jul2006          .   2181.597          .   2181.597 |
36. | 19467   10jul2006          .          .   1900.701   1900.701 |
37. | 19653   10jul2006          .          .   2373.175   2373.175 |
    |------------------------------------------------------------------------------------|
38. | 20048   10jul2006          .   946.1188          .   946.1188 |


I want to generate a new variable (tot_val) that is row sum of the three preceding variables (i.e valc200 valc150 valcrest). When I use egen tot_val=rsum(valc200 valc150 valcrest), as expected I get a sum which is equal to one of the variables because the other two have missing values. For instance in row 31 I get a total of 7358.771 which is the same as valc150 in that row.I think my problem is I need to get similar households(hhnr)to be in the same row (e.g. hhnr 18985 appears in rows 31 & 32 in the same day) to get their sum later. To do this I tried to reshape the data from long to wide but I am getting: hhnr not unique within mydate; this is because some households are reporting purchase of a given item twice within a same date.

Apart from the reshape attempt I feel I could have generated the above variables in a better way instead of: 
gen  valc200 =  valuewSADT if  cc200==1
gen  valc150 =  valuewSADT if  cc150==1
gen  valcrest =  valuewSADT if  ccrest==1

My final aim is to produce the totals and use them to derive expenditure shares
I would really be GRATEFUL to any explanations/tips.

Thanks

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