Replace values of one variable according to the categories of another

[jorge arenas molina]

Hi all!

I hope you can guide me in the following question. In te following dataset:

id Ya Yb id_2
1-1 .6249384 .7929984 1-1
1-1 . . 1-2
1-1 . . 2-1
1-2 . . 1-1
1-2 .6531338 .5850651 1-2
1-2 . . 2-1
2-1 . . 1-1
2-1 . . 1-2
2-1 .8717756 .890541 2-1

How can I replace the value of Ya for id == 1,1, for all observations that meet id == 1,1?
and so also for Yb, but with the variable id_2?

The goal is to get the following dataset:

id Ya Yb id_2
1-1 .6249384 .7929984 1-1
1-1 .6249384 .5850651 1-2
1-1 .6249384 .890541 2-1
1-2 .6531338 .7929984 1-1
1-2 .6531338 .5850651 1-2
1-2 .6531338 .890541 2-1
2-1 .8717756 .7929984 1-1
2-1 .8717756 .5850651 1-2
2-1 .8717756 .890541 2-1

Thank you very much in advance.

Greetings,

[Fei Wang]

* Example generated by -dataex-. For more info, type help dataex
clear
input str3 id float(Ya Yb) str3 id_2
"1-1" .6249384 .7929984 "1-1"
"1-1"        .        . "1-2"
"1-1"        .        . "2-1"
"1-2"        .        . "1-1"
"1-2" .6531338 .5850651 "1-2"
"1-2"        .        . "2-1"
"2-1"        .        . "1-1"
"2-1"        .        . "1-2"
"2-1" .8717756  .890541 "2-1"
end

bys id (Ya): replace Ya = Ya[_n-1] if mi(Ya)
bys id_2 (Yb): replace Yb = Yb[_n-1] if mi(Yb)

[Andrew Musau]

Assuming "Ya" and "Yb" are numeric variables:

bys id (Ya): replace Ya= Ya[1]
bys id_2 (Yb): replace Yb= Yb[1]