我将如何复制它plyr
?
with(mtcars, tapply(mpg, cyl, summary))
以同样的优雅,即没有拼出个人统计数据?
library(plyr)
dlply(mtcars, .(cyl), function(x) summary(x$mpg))
您也可以在 data.frame 中执行此操作,我通常更喜欢复杂列表...
ddply(mtcars, .(cyl), function(x) summary(x$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