不同的函数不一样。如sd,
看源码用 sd即可
> sd
function (x, na.rm = FALSE)
{
if (is.matrix(x))
apply(x, 2, sd, na.rm = na.rm)
else if (is.vector(x))
sqrt(var(x, na.rm = na.rm))
else if (is.data.frame(x))
sapply(x, sd, na.rm = na.rm)
else sqrt(var(as.vector(x), na.rm = na.rm))
}
<environment: namespace:stats>
>
若用sd.default 则错
而对hist
直接输入hist
hist
function (x, ...)
UseMethod("hist")
<environment: namespace:graphics>
这时则为hist.default