Construct an immutable data frame.
An immutable data frame works like an ordinary data frame, except that when you subset it, it returns a reference to the original data frame, not a a copy. This makes subsetting substantially faster and has a big impact when you are working with large datasets with many groups.
idata.frame(df)
df |
a data frame |
This method is still a little experimental, so please let me know if you run into any problems.
an immutable data frame
system.time(dlply(baseball, "id", nrow)) system.time(dlply(idata.frame(baseball), "id", nrow))
Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.