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@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.
