STATA date format

[andrew roder]

Dear All,

Can you help me in converting this date format

----------------------- copy starting from the next line -----------------------

* Example generated by -dataex-. For more info, type help dataex
clear
input str255 yearofrecord
"26/03/21"
"25/03/21"
"23/03/21"
"23/03/21"
"22/03/21"
"22/03/21"
"19/03/21"
"18/03/21"
"18/03/21"
"16/03/21"
"15/03/21"
"13/03/21"
"12/03/21"
"09/03/21"
"04/03/21"
"03/03/21"
"02/03/21"
"02/03/21"
"25/02/21"
"19/02/21"
"19/02/21"
"18/02/21"
"18/02/21"
"17/02/21"
"17/02/21"
"16/02/21"
"16/02/21"
"16/02/21"
"15/02/21"
"10/02/21"
"09/02/21"
"08/02/21"
"06/02/21"
"06/02/21"
"05/02/21"
"05/02/21"
"04/02/21"
"04/02/21"
"03/02/21"
"03/02/21"
"29/01/21"
"29/01/21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
"1-Jul-21"
end

Convert this string variable into date and extract the year from date variable.

Thank you

[Nick Cox]

Thanks for the data example. We don't need the duplicates.

If you all care about is the year, it's just the last two characters of the date string plus a century start. Alternatively, you can get a daily date and then pull the year out of that. Documentation at

help string functions 

help date functions

* Example generated by -dataex-. For more info, type help dataex
clear
input str255 yearofrecord
"26/03/21"
"25/03/21"
"23/03/21"
"22/03/21"
"19/03/21"
"18/03/21"
"16/03/21"
"15/03/21"
"13/03/21"
"12/03/21"
"09/03/21"
"04/03/21"
"03/03/21"
"02/03/21"
"25/02/21"
"19/02/21"
"18/02/21"
"17/02/21"
"16/02/21"
"15/02/21"
"10/02/21"
"09/02/21"
"08/02/21"
"06/02/21"
"05/02/21"
"04/02/21"
"03/02/21"
"29/01/21"
"1-Jul-21"
end

.  gen year1 = 2000 + real(substr(year, -2, 2))

. gen date = daily(yearofrecord, "DMY", 2025)

. format date %td

. gen year2 = year(date)

. assert year1 == year2

. list

     +--------------------------------------+
     | yearof~d   year1        date   year2 |
     |--------------------------------------|
  1. | 26/03/21    2021   26mar2021    2021 |
  2. | 25/03/21    2021   25mar2021    2021 |
  3. | 23/03/21    2021   23mar2021    2021 |
  4. | 22/03/21    2021   22mar2021    2021 |
  5. | 19/03/21    2021   19mar2021    2021 |
     |--------------------------------------|
  6. | 18/03/21    2021   18mar2021    2021 |
  7. | 16/03/21    2021   16mar2021    2021 |
  8. | 15/03/21    2021   15mar2021    2021 |
  9. | 13/03/21    2021   13mar2021    2021 |
 10. | 12/03/21    2021   12mar2021    2021 |
     |--------------------------------------|
 11. | 09/03/21    2021   09mar2021    2021 |
 12. | 04/03/21    2021   04mar2021    2021 |
 13. | 03/03/21    2021   03mar2021    2021 |
 14. | 02/03/21    2021   02mar2021    2021 |
 15. | 25/02/21    2021   25feb2021    2021 |
     |--------------------------------------|
 16. | 19/02/21    2021   19feb2021    2021 |
 17. | 18/02/21    2021   18feb2021    2021 |
 18. | 17/02/21    2021   17feb2021    2021 |
 19. | 16/02/21    2021   16feb2021    2021 |
 20. | 15/02/21    2021   15feb2021    2021 |
     |--------------------------------------|
 21. | 10/02/21    2021   10feb2021    2021 |
 22. | 09/02/21    2021   09feb2021    2021 |
 23. | 08/02/21    2021   08feb2021    2021 |
 24. | 06/02/21    2021   06feb2021    2021 |
 25. | 05/02/21    2021   05feb2021    2021 |
     |--------------------------------------|
 26. | 04/02/21    2021   04feb2021    2021 |
 27. | 03/02/21    2021   03feb2021    2021 |
 28. | 29/01/21    2021   29jan2021    2021 |
 29. | 1-Jul-21    2021   01jul2021    2021 |
     +--------------------------------------+

See also https://www.statalist.org/forums/help#spelling

[andrew roder]

Thank you . It works great