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select same row in a data frame several times

4 messages · Pedro Mardones, MacQueen, Don, Rolf Turner

#
Dear R user;

Consider the following toy example

A <- data.frame(ID1 = c(1,2,3,1,2,3,1,2,3), ID2 =
c("a","b","c","d","e","f","g","h","i"), stringsAsFactors = FALSE)
B <- sample(a$ID2, 6, replace = TRUE)

Lets say B is = "a", "a", "a", "h", "b", "e"

I want to extract from A the rows where ID2 == B. If I use
AA <- A[A$ID2 %in% B == TRUE,], I get only 1 row with ID2="a" instead of
the 3 rows I want.

Is it possible to easily implement this selection? (same row several times)

Thanks
Pedro
#
Try

B <- c("a", "a", "a", "h", "b", "e")
subset(A, ID2 %in% B)

or
  subset(A, ID2 %in% unique(B))
will do as well
#
Sorry, I was too quick.

Try
  A[ match(B, A$ID2) ,]
#
On 15/11/14 10:45, Pedro Mardones wrote:
AA <- A[match(B,A$ID2),]

cheers,

Rolf Turner

P.S. The syntax "A$ID2 %in% B == TRUE" is a message brought to you by 
the Department of Redundancy Department, and it drives me _crazy_!  Just 
use "A$ID2%in%B,".

If "v" is a logical vector then "v==TRUE" is identical to v.

See fortune(69).

R. T.