zwzcosname
fivenum是通过中位数计算的，summary是通过分位数计算的，是这样吗，：）
fivenum:
function (x, na.rm = TRUE)
{
xna <- is.na(x)
if (na.rm)
x <- x[!xna]
else if (any(xna))
return(rep.int(NA, 5))
x <- sort(x)
n <- length(x)
if (n == 0)
rep.int(NA, 5)
else {
n4 <- floor((n + 3)/2)/2
d <- c(1, n4, (n + 1)/2, n + 1 - n4, n)
0.5 * (x[floor(d)] + x[ceiling(d)])
}
}
summary.default:
else if (is.numeric(object)) {
nas <- is.na(object)
object <- object[!nas]
qq <- stats::quantile(object)
qq <- signif(c(qq[1:3], mean(object), qq[4:5]), digits)
names(qq) <- c("Min.", "1st Qu.", "Median", "Mean", "3rd Qu.",
"Max.")
if (any(nas))
c(qq, "NA's" = sum(nas))
else qq
}
