[R] deparse(substitute(foo))

[Armstrong, Whit]

I see that plot.default uses deparse(substitute(x)) to extract the
character name of an argument and put it on the vertical axis.

Hence:
foo <- 1:10
plot( foo )

will put the label "foo" on the vertical axis.

However, for a function that takes a "..." list as an input, I can only
extract the first argument name:

x <- 1:10
y <- 10:20

foo <- function(...) {
  print(deparse(substitute(...)))
}

foo(x,y)

returns: 

> foo(x,y) 
[1] "x"
> 

and when I try to convert the list to a local variable and then extract
names, that doesn't work either:

x <- 1:10 
y <- 10:20 
 
foo <- function(...) { 
 
    x <- list(...) 
    print(deparse(substitute(names(x)))) 
} 
 
foo(x,y) 

returns:

> foo(x,y)
[1] "names(list(c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10), c(10, 11, 12, 13, "
[2] "14, 15, 16, 17, 18, 19, 20)))"                                  
> 


Can someone suggest a way to extract the variable names when they are
passed as a list via "..." ?

Thanks,
Whit




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