2楼: Originally posted by FMStation at 2016-09-23 19:59:40
http://www.cnblogs.com/Bfrican/p/4430197.html

1）The simplest function for counting the number of observations that take on a value is the tabulate function。该函数对向量中的元素数量计数，接收每一 ...

> HR.cnts <- tabulate(batting.w.names.2008$HR)

> # tabulate doesn't label results, so let's add names:

> names(HR.cnts) <- 0:(length(HR.cnts) - 1)

table(..., exclude = if (useNA == "no") c(NA, NaN), useNA = c("no",
"ifany", "always"), dnn = list.names(...), deparse.level = 1)