[R] Replace missing value within group with non-missing value

[Rui Barradas]

Hello,

That's not a very good way of posting your data, preferably paste the 
output of ?dput in a post.
Some thing along the lines of the following might do what you want. It 
seems that the groups are established by 'dn' and 'obs' numbers. If so, try


# Make up some data
dat <- data.frame(dn = 4, obs = rep(1:5, each = 6), mth = NA)
dat$mth[6] <- 487
dat$mth[9] <- 488
dat$mth[18] <- 488
dat$mth[21] <- 489
dat$mth[30] <- 489


sp <- split(dat, list(dat$dn, dat$obs))
names(sp) <- NULL
tmp <- lapply(sp, function(x){
		idx <- which(!is.na(x$mth))[1]
		x$mth <- x$mth[idx]
		x
	})
do.call(rbind, tmp)


Hope this helps,

Rui Barradas


Em 06-04-2013 11:33, Leask, Graham escreveu:
> 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]]
>
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