I am basically trying to append a value(vector) to one dataframe using a relational value from another dataframe. Obviously, I can use a loop to accomplish this. However, is there a way to vectorize it? Example:> data <- data.frame(c(1,1,1,2,2,2,3,3,3),rep(2,9)); names(data) <- > c("Sample","Score") > meta <- data.frame(c(1,2,3),c("Tree","Tree","Shrub")); names(meta) <- > c("Sample","Stratum")The following attempt at vectorizaton doesn't work:> data$Stratum <- meta$Stratum[which(data$Sample == meta$Sample)]> data$Stratum[1] Tree <NA> <NA> Tree <NA> <NA> Tree <NA> <NA> And actually, when I try to run a loop, the operation converts the string to a factor.> for (i in 1:length(data[,1])) data$Stratum[i] <- > meta$Stratum[which(meta$Sample == data$Sample[i])]>dataSample Score Stratum 1 1 2 2 2 1 2 2 3 1 2 2 4 2 2 2 5 2 2 2 6 2 2 2 7 3 2 1 8 3 2 1 9 3 2 1 Argghhhh....I don't want a factor, and anyway I don't want to use a loop... Can anyone help with these two issues??? -- View this message in context: http://www.nabble.com/how-do-i-vectorize-relational-queries-in-R-tp25052929p25052929.html Sent from the R help mailing list archive at Nabble.com.
Is this what you want:> data$Stratum <- meta$Stratum[data$Sample] > dataSample Score Stratum 1 1 2 Tree 2 1 2 Tree 3 1 2 Tree 4 2 2 Tree 5 2 2 Tree 6 2 2 Tree 7 3 2 Shrub 8 3 2 Shrub 9 3 2 Shrub>On Wed, Aug 19, 2009 at 6:21 PM, chipmaney<chipmaney at hotmail.com> wrote:> > I am basically trying to append a value(vector) to one dataframe using a > relational value from another dataframe. ?Obviously, I can use a loop to > accomplish this. ?However, is there a way to vectorize it? > > Example: > >> data <- data.frame(c(1,1,1,2,2,2,3,3,3),rep(2,9)); names(data) <- >> c("Sample","Score") >> meta <- data.frame(c(1,2,3),c("Tree","Tree","Shrub")); names(meta) <- >> c("Sample","Stratum") > > > The following attempt at vectorizaton doesn't work: > >> data$Stratum <- meta$Stratum[which(data$Sample == meta$Sample)] > >> data$Stratum > [1] Tree <NA> <NA> Tree <NA> <NA> Tree <NA> <NA> > > And actually, when I try to run a loop, the operation converts the string to > a factor. > >> for (i in 1:length(data[,1])) data$Stratum[i] <- >> meta$Stratum[which(meta$Sample == data$Sample[i])] > >>data > ?Sample Score Stratum > 1 ? ? ?1 ? ? 2 ? ? ? 2 > 2 ? ? ?1 ? ? 2 ? ? ? 2 > 3 ? ? ?1 ? ? 2 ? ? ? 2 > 4 ? ? ?2 ? ? 2 ? ? ? 2 > 5 ? ? ?2 ? ? 2 ? ? ? 2 > 6 ? ? ?2 ? ? 2 ? ? ? 2 > 7 ? ? ?3 ? ? 2 ? ? ? 1 > 8 ? ? ?3 ? ? 2 ? ? ? 1 > 9 ? ? ?3 ? ? 2 ? ? ? 1 > > Argghhhh....I don't want a factor, and anyway I don't want to use a loop... > > Can anyone help with these two issues??? > -- > View this message in context: http://www.nabble.com/how-do-i-vectorize-relational-queries-in-R-tp25052929p25052929.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. >-- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve?
Does
merge(data,meta)
give what you want?
FWIW:
"append" to a dataframe would normally mean to add more rows (or at
least that's how I use it), but you appear to be adding a column.
"data" is the name of an R function, best avoided for other uses.
You're assigning the column names the hard way. Try
mydata <- data.frame(Sample=c(1,1,1,2,2,2,3,3,3), Score=rep(2,9))
To avoid the factors, use
meta <- data.frame(Score=c(1,2,3), Stratum =
I(c("Tree","Tree","Shrub")) )
## that's an upper case letter "i" in I()
or
meta <- data.frame(Score=c(1,2,3), Stratum =
c("Tree","Tree","Shrub"), stringsAsFactors=FALSE )
## easily found in the help page for data.frame
-Don
At 3:21 PM -0700 8/19/09, chipmaney wrote:>I am basically trying to append a value(vector) to one dataframe using a
>relational value from another dataframe. Obviously, I can use a loop to
>accomplish this. However, is there a way to vectorize it?
>
>Example:
>
> > data <- data.frame(c(1,1,1,2,2,2,3,3,3),rep(2,9)); names(data)
<-
>> c("Sample","Score")
> > meta <-
data.frame(c(1,2,3),c("Tree","Tree","Shrub"));
names(meta) <-
>> c("Sample","Stratum")
>
>
>The following attempt at vectorizaton doesn't work:
>
>> data$Stratum <- meta$Stratum[which(data$Sample == meta$Sample)]
>
>> data$Stratum
>[1] Tree <NA> <NA> Tree <NA> <NA> Tree <NA>
<NA>
>
>And actually, when I try to run a loop, the operation converts the string to
>a factor.
>
>> for (i in 1:length(data[,1])) data$Stratum[i] <-
>> meta$Stratum[which(meta$Sample == data$Sample[i])]
>
>>data
> Sample Score Stratum
>1 1 2 2
>2 1 2 2
>3 1 2 2
>4 2 2 2
>5 2 2 2
>6 2 2 2
>7 3 2 1
>8 3 2 1
>9 3 2 1
>
>Argghhhh....I don't want a factor, and anyway I don't want to use a
loop...
>
>Can anyone help with these two issues???
>--
>View this message in context:
>http://*www.*nabble.com/how-do-i-vectorize-relational-queries-in-R-tp25052929p25052929.html
>Sent from the R help mailing list archive at Nabble.com.
>
>______________________________________________
>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.
--
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
925-423-1062