In R, how to split/subset a data frame by factors in one column?

按照某列的值拆分data.frame

My data is like this (for example):

ID  Rate    State
1   24  AL
2   35  MN
3   46  FL
4   34  AL
5   78  MN
6   99  FL

I want to split the data by state and I want to get 3 data sets like below:

data set 1
ID  Rate    State
1   24  AL
4   34  AL
data set 2
ID  Rate    State
2   35  MN
5   78  MN
data set 3
ID  Rate    State
3   46  FL
6   99  FL

split( df , df$State )$AL  ID Rate State1  1   24    AL4  4   34    AL

$FL  ID Rate State3  3   46    FL6  6   99    FL

$MN  ID Rate State2  2   35    MN5  5   78    MN

mylist <- split( df , df$State ) ; mylist[[1]]mylist[[2]]mylist[[3]]

REF:http://stackoverflow.com/questions/19327020/in-r-how-to-split-subset-a-data-frame-by-factors-in-one-column