Fillin with incomplete data

[Raph Selenite]

Hello,

I want to use fillin to complete my data but i have missing categories in my group variable.

I have this :

* Example generated by -dataex-. For more info, type help dataex
clear
input float(id group)
1 1
1 2
1 4
1 5
2 1
2 2
2 5
end

In my data there is only 1 2 4 5 for the variable group. But i want something like that (with the value 3 in group) :

* Example generated by -dataex-. For more info, type help dataex
clear
input float(id group)
1 1
1 2
1 3
1 4
1 5
2 1
2 2
2 3
2 4
2 5
end

Is it possible to get that with Fillin ? Or an other solution ?

Thanks !

[Nick Cox]

This is discussed in

SJ-5-1  dm0011  . . . . . . . . . . . . . .  Stata tip 17: Filling in the gaps
        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  N. J. Cox
        Q1/05   SJ 5(1):135--136                                 (no commands)
        tips for using fillin to fill in gaps in a rectangular
        data structure

which in turn is referenced in the manual entry for fillin.

* Example generated by -dataex-. For more info, type help dataex
clear
input float(id group)
1 1
1 2
1 4
1 5
2 1
2 2
2 5
end

expand 2 in L 
replace group = 3 in L 

fillin id group

list