Adding lines of data by an identifier

[Gianni Spolver]

Hi,

I can't seem to get my head around an issue. So basically I have a dataset with a set of identifers named ID. For each year I have a variable named Entry and a variable Exit. Both Entry and Exit provide a year. The objective would be to create a new "Year" variable and add a line of data for each year between Entry and Exit. So for instance if for ID = 1 Entry would be 2000 and exit 2003 and for ID = 2 Entry would be 2018 and Exit 2020; the final result I would need is:

ID	Entry	Exit	Year
1	2000	2003	2000
1	2000	2003	2001
1	2000	2003	2002
1	2000	2003	2003
2	2018	2020	2018
2	2018	2020	2019
2	2018	2020	2020

Could anyone help me with setting this up?

Kind regards,

Gianni

[Nick Cox]

Please use dataex as explained in FAQ Advice #12. I could create a data example from your clear question but that's your job. (Insert emoticon of choice.)

clear 
input ID Entry Exit 
1 2000 2003
2 2018 2020
end 

gen toexpand = Exit - Entry + 1 

expand toexpand 

bysort ID : gen date = Entry + _n - 1 

list, sepby(ID)

     +-------------------------------------+
     | ID   Entry   Exit   toexpand   date |
     |-------------------------------------|
  1. |  1    2000   2003          4   2000 |
  2. |  1    2000   2003          4   2001 |
  3. |  1    2000   2003          4   2002 |
  4. |  1    2000   2003          4   2003 |
     |-------------------------------------|
  5. |  2    2018   2020          3   2018 |
  6. |  2    2018   2020          3   2019 |
  7. |  2    2018   2020          3   2020 |
     +-------------------------------------+