On Feb 22, 2010, at 8:45 AM, statquant wrote:
Hello Sarah, thanks for answering
For example if I have the following example
test <- as.data.frame(matrix(c(1,2,3,4, 11,12,13,14,
"a","b","b","c"), nrow
= 3, ncol=3,dimnames = list(c("r1","r2","r3","r4"),NULL))
This is a malformed example. Should be:
> test <- as.data.frame(matrix(c(1,2,3,4, 11,12,13,14,
"a","b","b","c"), nrow= 4, ncol=3,dimnames =
list(c("r1","r2","r3","r4"),NULL)) )
> test
V1 V2 V3
r1 1 11 a
r2 2 12 b
r3 3 13 b
r4 4 14 c
V1 V2 V3
r1 1 11 a
r2 2 12 b
r3 3 13 b
r4 4 14 c
it is easy to select test <- test[,mylist] with for example mylist <-
c("V1","V3")
V1 V3
r1 1 a
r2 2 b
r3 3 b
r4 4 c
But after how can I restrict test in selecting the rows where the
result in
column V3 are in a list mylist2, with for example mylist2 <-
c("b","c","d") ?
which would give as an example
?"%in%"
?"["
?subset
> test[test$V3 %in% c("b","c","d"), c("V1","V2")]
V1 V2
r2 2 12
r3 3 13
r4 4 14
#Or:
> subset(test, V3 %in% c("b","c","d"), select=c(V1, V3))
V1 V3
r2 2 b
r3 3 b
r4 4 c
V1 V3
r2 2 b
r3 3 b
r4 4 c
Regards
Colin
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