R help - Jun 2010 - Function argument as string

Hi,

Suppose a write a function

a_fn<-function(arg1)
{

    return(table(arg1));
}

I have a column called AGE. Now I call the function c = a_fn(AGE);

When a_fn is called, AGE is received in arg1. My question is, how do I
access  the actual name of the argument arg1? i.e, inside the
function, i need to know that the actual name of arg1 is "AGE" in this
case.

Thanks in advance,
Vishwanath

Vishwanath Sindagi wrote:
> Hi,
> 
> Suppose a write a function
> 
> a_fn<-function(arg1)
> {
> 
>     return(table(arg1));
> }
> 
> I have a column called AGE. Now I call the function c = a_fn(AGE);
> 
> When a_fn is called, AGE is received in arg1. My question is, how do I
> access  the actual name of the argument arg1? i.e, inside the
> function, i need to know that the actual name of arg1 is "AGE" in
this
> case.
Is this what you mean ?

fun <- function(x) {
   as.character(substitute(x))
}

 > fun(age)
[1] "age"

Try

# data
AGE <- rpois(25, 30)

# option 1
foo <- function(string) table(get(deparse(substitute(string))))
foo(AGE)    # no quotes

# option 2
foo2 <- function(string) table(get(string))
foo2('AGE')  # note the quotes here

HTH,
Jorge


On Wed, Jun 16, 2010 at 11:30 AM, Vishwanath Sindagi <> wrote:
> Hi,
>
> Suppose a write a function
>
> a_fn<-function(arg1)
> {
>
>    return(table(arg1));
> }
>
> I have a column called AGE. Now I call the function c = a_fn(AGE);
>
> When a_fn is called, AGE is received in arg1. My question is, how do I
> access  the actual name of the argument arg1? i.e, inside the
> function, i need to know that the actual name of arg1 is "AGE" in
this
> case.
>
> Thanks in advance,
> Vishwanath
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

Perfect. Thanks Erik.

On Thu, Jun 17, 2010 at 1:07 AM, Erik Iverson <eriki at ccbr.umn.edu>
wrote:
>
>
> Vishwanath Sindagi wrote:
>>
>> Hi,
>>
>> Suppose a write a function
>>
>> a_fn<-function(arg1)
>> {
>>
>> ? ?return(table(arg1));
>> }
>>
>> I have a column called AGE. Now I call the function c = a_fn(AGE);
>>
>> When a_fn is called, AGE is received in arg1. My question is, how do I
>> access ?the actual name of the argument arg1? i.e, inside the
>> function, i need to know that the actual name of arg1 is
"AGE" in this
>> case.
>
> Is this what you mean ?
>
> fun <- function(x) {
> ?as.character(substitute(x))
> }
>
>> fun(age)
> [1] "age"
>