r - dplyr summarize: how to include all table columns in the output table -

i have follow dataset

# dataset x<-tbl_df(data.frame(locus=c(1,2,2,3,4,4,5,5,5,6),v=c(1,1,2,1,1,2,1,2,3,1),rpkm=rnorm(10,10)))

if use follow command

# subset x%>%group_by(locus)%>%summarize(max(rpkm))

i obtained

locus max(rpkm) 1     9.316949 2     10.273270 3     9.879886 4     10.944641 5     10.837681 6     13.450680

while i'd obtain

locus v  max(rpkm) 1     1  9.316949 2     1  10.273270 3     1  9.879886 4     2 10.944641 5     1 10.837681 6     1 13.450680

so, i'd have in output table "v" correspondent row. possible?

try:

x %>% group_by(locus) %>%       summarize(max(rpkm), v = v[which(rpkm==max(rpkm))])

JVParth