Hi Kohleth,
Suppose this is my list of transactions:
set.seed(200)
tran=random.transactions(100,3)
inspect(tran)
items transactionID
1 {item80} trans1
2 {item8,
item20} trans2
3 {item28} trans3
I want to get the 'transpose' of the data, i.e.
transactionID items
1 {trans2} item8
2 {trans2} item20
3 {trans3} item28
4 {trans1} item80
This is not the transpose. The data structure you want can be created
this way:
> l <- LIST(tran)
> single <- data.frame(ID=rep(names(l), lapply(l, length)),
items=unlist(l), row.names=NULL)
> single
ID items
1 trans1 item80
2 trans2 item8
3 trans2 item20
4 trans3 item28
I tried converting tran into a matrix, then transpose it, then convert it
back to transactions. But my dataset is actually very very large, so I
wonder if there is any faster method?
The method above should be very fast.
-Michael
Thanks
--
Dr. Michael Hahsler, Visiting Assistant Professor
Department of Computer Science and Engineering
Lyle School of Engineering
Southern Methodist University, Dallas, Texas
(214) 768-8878 * mhahs...@lyle.smu.edu * http://lyle.smu.edu/~mhahsler
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