Dear List members I have a large dataset organised in choice groups see sample below
+-------------------------------------------------------------------------------------------------+ | dn obs choice acid br date cdate situat~n mth year set | |-------------------------------------------------------------------------------------------------| 1. | 4 1 0 LOSEC 1 . . . . 1 | 2. | 4 1 0 NEXIUM 2 . . . . 1 | 3. | 4 1 0 PARIET 3 . . . . 1 | 4. | 4 1 0 PROTIUM 4 . . . . 1 | 5. | 4 1 0 ZANTAC 5 . . . . 1 | |-------------------------------------------------------------------------------------------------| 6. | 4 1 1 ZOTON 6 23aug2000 01:00:00 23aug2000 NS 487 2000 1 | 7. | 4 2 0 LOSEC 1 . . . . 2 | 8. | 4 2 0 NEXIUM 2 . . . . 2 | 9. | 4 2 1 PARIET 3 25sep2000 01:00:00 25sep2000 L 488 2000 2 | 10. | 4 2 0 PROTIUM 4 . . . . 2 | |-------------------------------------------------------------------------------------------------| 11. | 4 2 0 ZANTAC 5 . . . . 2 | 12. | 4 2 0 ZOTON 6 . . . . 2 | 13. | 4 3 0 LOSEC 1 . . . . 3 | 14. | 4 3 0 NEXIUM 2 . . . . 3 | 15. | 4 3 0 PARIET 3 . . . . 3 | |-------------------------------------------------------------------------------------------------| 16. | 4 3 0 PROTIUM 4 . . . . 3 | 17. | 4 3 0 ZANTAC 5 . . . . 3 | 18. | 4 3 1 ZOTON 6 20sep2000 00:00:00 20sep2000 R 488 2000 3 | 19. | 4 4 0 LOSEC 1 . . . . 4 | 20. | 4 4 0 NEXIUM 2 . . . . 4 | |-------------------------------------------------------------------------------------------------| 21. | 4 4 1 PARIET 3 27oct2000 00:00:00 27oct2000 NL 489 2000 4 | 22. | 4 4 0 PROTIUM 4 . . . . 4 | 23. | 4 4 0 ZANTAC 5 . . . . 4 | 24. | 4 4 0 ZOTON 6 . . . . 4 | 25. | 4 5 0 LOSEC 1 . . . . 5 | |-------------------------------------------------------------------------------------------------| 26. | 4 5 0 NEXIUM 2 . . . . 5 | 27. | 4 5 0 PARIET 3 . . . . 5 | 28. | 4 5 0 PROTIUM 4 . . . . 5 | 29. | 4 5 0 ZANTAC 5 . . . . 5 | 30. | 4 5 1 ZOTON 6 23oct2000 03:00:00 23oct2000 NS 489 2000 5 | I wish to fill in the missing values in each choice set - delineated by dn (Doctor) obs (Observation number) and choices (1 to 6). For each choice set one choice is chosen which contains full time information for that choice set ie in set 1 choice 6 was chosen and shows the month 487. The other 5 choices show mth as missing. I want to fill these with the correct mth. I am sure there must be an elegant way to do this in R? Best wishes Graham [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.