R in ddply (plyr) in a simple way

Question

How would I replicate this using plyr ?

with(mtcars, tapply(mpg, cyl, summary))

With the same elegance, that is, without writing separate statistics?

Answer 1

 library(plyr) dlply(mtcars, .(cyl), function(x) summary(x$mpg)) 

You can also do this in data.frame, which I usually prefer over complex lists ...

 ddply(mtcars, .(cyl), function(x) summary(x$mpg)) # cyl Min. 1st Qu. Median Mean 3rd Qu. Max. # 1 4 21.4 22.80 26.0 26.66 30.40 33.9 # 2 6 17.8 18.65 19.7 19.74 21.00 21.4 # 3 8 10.4 14.40 15.2 15.10 16.25 19.2