[R] the "union" of several data frame rows

[Henrique Dallazuanna]

Perhaps:

data <- data.frame(key, row.names=1)
names(data) <- paste("q", 1:6, sep="")
apply(data, 2, function(x)unique(x)[unique(x) != " "])


On 01/02/2008, Scot W. McNary <smcnary at charm.net> wrote:
> Hi,
>
> I have a question about how to obtain the union of several data frame
> rows.  I'm trying to create a common key for several tests composed of
> different items.   Here is a small scale version of the problem.  These
> are keys for 4 different tests, not all mutually exclusive:
>
> id q1 q2 q3 q4 q5 q6
> 1  A  C
> 2              B  D
> 3  A     D  B
> 4     C  D     B  D
>
> I would like to create a single key all test versions, the "union" of
> the above:
>
> id   q1 q2 q3 q4 q5 q6
> key  A  C  D  B  B  D
>
>
> Here is what I have (unsuccessfully) tried so far:
>
>  > key <-
> +   matrix(c("1", "A", "C", " ", " ", " ", " ",
> +          "2", " ", " ", " ", " ", "B", "D",
> +          "3", "A", " ", "D", "B", " ", " ",
> +          "4", " ", "C", "D", " ", "B", "D"),
> +        byrow=TRUE, ncol = 7)
>  >
>  > k1 <- key[1, 2:7]
>  > k2 <- key[2, 2:7]
>  > k3 <- key[3, 2:7]
>  > k4 <- key[4, 2:7]
>  >
>  > itemid <- c("q1", "q2", "q3", "q4", "q5", "q6")
>  >
>  > k1 <- cbind(itemid, k1)
>  > k2 <- cbind(itemid, k2)
>  > k3 <- cbind(itemid, k3)
>  > k4 <- cbind(itemid, k4)
>  >
>  > tmp <- merge(k1, k2, by = "itemid")
>  > tmp <- merge(tmp, k3, by = "itemid")
>  > tmp <- merge(tmp, k4, by = "itemid")
>  >
>  > t(tmp)
>        [,1] [,2] [,3] [,4] [,5] [,6]
> itemid "q1" "q2" "q3" "q4" "q5" "q6"
> k1     "A"  "C"  " "  " "  " "  " "
> k2     " "  " "  " "  " "  "B"  "D"
> k3     "A"  " "  "D"  "B"  " "  " "
> k4     " "  "C"  "D"  " "  "B"  "D"
>
> The actual problem involves 300 or so items instead of 6 and 10
> different keys instead of four.  Any suggestions welcome.
>
> Thanks in advance,
>
> Scot McNary
>
>  > version
>                _
> platform       i386-pc-mingw32
> arch           i386
> os             mingw32
> system         i386, mingw32
> status
> major          2
> minor          6.1
> year           2007
> month          11
> day            26
> svn rev        43537
> language       R
> version.string R version 2.6.1 (2007-11-26)
>
>
> --
> Scot McNary
> smcnary at charm dot net
>
> ______________________________________________
> R-help at 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.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O