Dealing with numbers from different rows

[Esteban Jara]

Hello. I have a dataset like this:

* Example generated by -dataex-. To install: ssc install dataex
clear
input byte(x1 x2) int x3 byte c
1 1 121 .
2 2 133 .
3 3 132 .
4 4 144 .
end

I need to give this instruction: in the row where x1 == 3, replace the value of c with the value of x3 when x2 == 2. The result must be like this:

* Example generated by -dataex-. To install: ssc install dataex
clear
input byte(x1 x2) int(x3 c)
1 1 121   .
2 2 133   .
3 3 132 133
4 4 144   .
end

How can I do this?

Thanks

[Øyvind Snilsberg]

perhaps,

replace c = x3[_n-1] if x1==3

[Esteban Jara]

It doesn't work for me, because I need the result to depend on the value of x1 and x2, not the row number itself. Thank you anyway

[Øyvind Snilsberg]

I see. How about,

sum x3 if x2==2
replace c = r(mean) if x1==3

?

[Esteban Jara]

It worked great! However, it strikes me that apparently this cannot be done through subscripting... thank you very much!