How to split a data frame?

Question

I want to split a data frame into several smaller ones. This looks like a very trivial question, however I cannot find a solution from web search.

Answer 1

If you want to split by values in one of the columns, you can use lapply. For instance, to split ChickWeight into a separate dataset for each chick:

data(ChickWeight)
lapply(unique(ChickWeight$Chick), function(x) ChickWeight[ChickWeight$Chick == x,])