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???
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