In R, how can I determine the number of arguments a function expects?
在R中，如何确定函数所期望的参数数量？
fa = function(x){}
fb = function(x,y){}
fc = function(x,y,z){}
So I want to define a function, f, where:
所以我想定义一个函数f，其中：
f(fa) = 1
f(fb) = 2
f(fc) = 3
and so forth...
等等......
Basically, I would like the utility of nargs() but from outside the function in question.
基本上，我想从nargs（）的实用程序，但从有问题的函数外部。
The reason for the above, is that I need to know the number of arguments that a function expects, for a specific implementation of optim(...), where the function being optimised is determined and generated at runtime.
上面的原因是，我需要知道函数所期望的参数个数，对于optim（...）的特定实现，其中优化的函数是在运行时确定并生成的。
1 个解决方案
#1
8
A possible approach:
一种可能的方法：
b <- function(x, y) {}
length(formals(b))
# [1] 2
#1
8
A possible approach:
一种可能的方法：
b <- function(x, y) {}
length(formals(b))
# [1] 2