[R] Matching

Gabor Grothendieck ggrothendieck at gmail.com
Mon Dec 22 17:25:01 CET 2008


Try this:

> Lines1 <- "names,values
+ A,1
+ B,2
+ C,3
+ D,4"
>
> Lines2 <- "names
+ A
+ C"
>
> DF1 <- read.csv(textConnection(Lines1))
> DF2 <- read.csv(textConnection(Lines2))
> merge(DF1, DF2)
  names values
1     A      1
2     C      3


On Mon, Dec 22, 2008 at 11:03 AM, vpas <vic.pascow at gmail.com> wrote:
>
> I understand this is an easy question, and have been playing around with grep
> and the match function, but was hoping for a little incite:
>
> I have one .csv with the following data:
>
> names values
> A        1
> B        2
> C        3
> D        4
>
>
> The second .csv is:
>
> names
> A
> C
>
>
> I am hoping to match all of the rows that appear in the second .csv, making
> a new file that would look like this:
>
> names values
> A        1
> C        3
>
>
> Here is what I have so far:
>
> my.data <- read.csv("rows.csv",sep=",")
> my.selection <- read.csv("select.csv",sep=",")
> matched <- match(my.data[,1], my.selection[,1])
> my.data <- my.data[matched]
> write.table(as.matrix(my.data), "select_RESULTS.txt")
>
> Unfortunately, this is throwing errors in row numbers...
>
> --
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>
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