如何獲取傳遞給...的參數的名稱？

Question

可能重複：
using substitute to get argument name with

注意，這是從獲得矢量自己與list(...)或那種形式的東西-different-。我希望能夠做的只是'回聲'所有參數傳遞到...，在任何解析完成之前。

如：我想這可能只是行事像一個函數：

f(apple, banana, car) 
## --> returns c("apple", "banana", "car"), 
## ie, skips looking for the objects apple, banana, car 

我已經得到的最接近的是

f <- function(...) { 
    return(deparse(substitute(...))) 
} 

但這只是返回第一個參數由...「抓」 。思考？

Answer 1

f <- 
    function(...){ 
    match.call(expand.dots = FALSE)$`...` 
    } 

一些explnation match.call：

1. match.call returns a call in which all of the specified arguments are specified by their full names . 
2. Here it is used to pass most of the call to another function, often model.frame. 
    Here the common idiom is that expand.dots = FALSE 

這裏一些測試：

f(2)  # call of a static argument 
[[1]] 
[1] 2 

> f(x=2) # call of setted argument 
$x 
[1] 2 

> f(x=y) # call of symbolic argument 
$x 
y