[R] Split a DF on Date column for each single year

[Ek Esawi]

Hi All—

I have a data frame with over 13000 rows and 4 columns. A mini data
frame is given at the bottom. I want to split the data frame into
lists each corresponds to single year which ranges from 1990 to 2018).
I wanted to use the split function, but it requires a vector of the
same length as MyDate which contains many multiples of each year.
Any help is highly appreciated.

I want the following results:
List 1990
MyDate MyNo MyDes
1990
1990
1990
…...
List 2000
2000
2000
2000
…...
List 2001
2001
2001
2001
2001
…...
List 2018
2018
2018
2018
…...

Sample data frame

mydf <- data.frame(MyDate=c("1990-01-01","1990-04-07","2000-04-05","2018-01-04"),MyNo=c(1,2,3,4),MyDes=c("AA","BB","CC","DD"))


EK