Is this what you want:
> data$Stratum <- meta$Stratum[data$Sample]
> data
Sample Score Stratum
1 1 2 Tree
2 1 2 Tree
3 1 2 Tree
4 2 2 Tree
5 2 2 Tree
6 2 2 Tree
7 3 2 Shrub
8 3 2 Shrub
9 3 2 Shrub
>
On Wed, Aug 19, 2009 at 6:21 PM, chipmaney<chipma...@hotmail.com> wrote:
>
> I am basically trying to append a value(vector) to one dataframe using a
> relational value from another dataframe. Obviously, I can use a loop to
> accomplish this. However, is there a way to vectorize it?
>
> Example:
>
>> data <- data.frame(c(1,1,1,2,2,2,3,3,3),rep(2,9)); names(data) <-
>> c("Sample","Score")
>> meta <- data.frame(c(1,2,3),c("Tree","Tree","Shrub")); names(meta) <-
>> c("Sample","Stratum")
>
>
> The following attempt at vectorizaton doesn't work:
>
>> data$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.
>
> ______________________________________________
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> 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?
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