View built-in dataset from a package

Question

I have installed the packages arules. How can I view the built-in dataset as usual?

I tried:

library(arules)
data(Groceries)
Groceries

While it only offer me:

transactions in sparse format with
 9835 transactions (rows) and
 169 items (columns)

What is sparse format?

Answer 1

inspect(Adult)
inspect(Adult[1:10,1:10])

inspect(Groceries)