如何检查函数在R中期望的最少参数个数？

要找到函数在R中使用时期望的最少数量的参数，可以借助以下语法来完成：length（formals（“ function_name”））。例如，要查找dplyr软件包的mutate函数期望的参数数量，可以使用命令length（formals(mutate)）计算出来，但是我们需要确保已加载该软件包。

例子

library(ggplot2)
length(formals(ggplot))

[1] 4
length(formals(boxplot))
[1] 2
length(formals(qnorm))
[1] 5
length(formals(rnorm))
[1] 3
length(formals(rpois))
[1] 2
length(formals(runif))
[1] 3
length(formals(punif))
[1] 5
length(formals(plot))
[1] 3
length(formals(pbinom))
[1] 5
length(formals(qbinom))
[1] 5
length(formals(hist))
[1] 2
length(formals(data))
[1] 7
length(formals(matrix))
[1] 5
length(formals(list))
[1] 0
length(formals(data.frame))
[1] 6
length(formals(paste))
[1] 4
length(formals(gsub))
[1] 7
length(formals(factor))
[1] 6
length(formals(cut))
[1] 2
length(formals(t.test))
[1] 2
length(formals(lm))
[1] 14
length(formals(glm))
[1] 18
length(formals(prop.test))
[1] 6
length(formals(pairwise.t.test))
[1] 7
length(formals(aov))
[1] 6
length(formals(dunif))
[1] 4
length(formals(dpois))
[1] 3
length(formals(dnorm))
[1] 4
length(formals(cbind))
[1] 2
length(formals(rbind))
[1] 2
length(formals(cor))
[1] 4
length(formals(cor.test))
[1] 2
length(formals(mean))
[1] 2
length(formals(sum))
[1] 0
length(formals(median))
[1] 3
length(formals(quantile))
[1] 2
length(formals(rank))
[1] 3
length(formals(var))
[1] 4
length(formals(sd))
[1] 2
length(formals(round))
[1] 0