如何使用该调用的另一个参数以及在R中的函数环境内部创建的对象求值该函数调用的一个参数？

Question

I am trying to write a function that will take an expression as an argument, and then evaluate that expression in the context of 1) another argument of the function, and 2) an object created inside the function itself.

I'm having some problems getting the environment to work. Does anyone know how to do this?

myfun <- function(es = .5, model = es * x[, 1]){
  x <- matrix(rnorm(300), ncol = 3)
  mu <- eval(model)
  mu
}

myfun(es = .8, model = es * x[, 1] + es * x[, 1]^2 + es * x[, 1]^3)

Results in the error: Error in eval(model) : object 'es' not found

Any suggestions?

Answer 1

Try substitute :

myfun <- function(es = .5, model = es * x[, 1]){
    x <- matrix(rnorm(300), ncol = 3)
    mu <- eval(substitute(model))
    mu
}