作为其他答案的补充，您可以使用 dplyr 。

As an addition to the other answers, you could do it with dplyr.

require(dplyr)

airquality %.%
  group_by(Month) %.%
  summarize(incomplete = sum(!complete.cases(Ozone, Solar.R)),
             complete = sum(complete.cases(Ozone, Solar.R)))

#  Month incomplete complete
#1     5          7       24
#2     6         21        9
#3     7          5       26
#4     8          8       23
#5     9          1       29