On 15/11/14 10:45, Pedro Mardones wrote:
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)
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.
--
Rolf Turner
Technical Editor ANZJS
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