how to delete duplicates by unit across group

[Daniela Rodrigues]

Hello,

I have the following dataset:

individual group
1111 0
1111 0
1111 1
1111 1
2222 1
2222 1
3213 0
3213 0
3213 0
3213 1
3213 1
3213 1
3213 1
3213 1
3444 0
3444 0
3444 0

In case the individual is both in group 0 and 1 (e.g. 1111, 3213) I would like to delete all observations related to that individual from group 0. For example, I would like to end up with:

individual group
1111 1
1111 1
2222 1
2222 1
3213 1
3213 1
3213 1
3213 1
3213 1
3444 0
3444 0
3444 0

Does anyone know a quick way to do this? Thank you.

[William Lisowski]

* Example generated by -dataex-. For more info, type help dataex
clear
input int individual byte group
1111 0
1111 0
1111 1
1111 1
2222 1
2222 1
3213 0
3213 0
3213 0
3213 1
3213 1
3213 1
3213 1
3213 1
3444 0
3444 0
3444 0
end
bysort individual (group): drop if group[_N]==1 & group==0
list, sepby(individual) abbreviate(12)

. list, sepby(individual) abbreviate(12)

     +--------------------+
     | individual   group |
     |--------------------|
  1. |       1111       1 |
  2. |       1111       1 |
     |--------------------|
  3. |       2222       1 |
  4. |       2222       1 |
     |--------------------|
  5. |       3213       1 |
  6. |       3213       1 |
  7. |       3213       1 |
  8. |       3213       1 |
  9. |       3213       1 |
     |--------------------|
 10. |       3444       0 |
 11. |       3444       0 |
 12. |       3444       0 |
     +--------------------+

[Daniela Rodrigues]

Thanks very much William Lisowski - it works perfectly.