Dear all,
I'm puzzled by the following example inspired by a recent question on
R-help,
cc <- textConnection("user_id website time
20 google 0930
21 yahoo 0935
20 facebook 1000
25 facebook 1015
61 google 0940")
d <- read.table(cc, head=T) ; close(cc)
table(d$user_id) # count the occurrences
# now I'd like to include these results in the original data.frame,
ddply(d, .(website), transform, count = table(user_id)) # why two new
columns?
I just can't understand how this is different from,
ddply(d, .(website), transform, count = sum(user_id))
Many thanks,
baptiste