R help - Apr 2011 - function in argument

Hi, I tried to pass the function dist() as an argument, but got an error 
message. However, almost the same code with mean() as the function to be passed,
it works ok.

foo<-function (x,
    xfun = dist) 
{
 xfun(x)
}

foo(matrix(1:100,nrow=5))
Error in foo(matrix(1:100, nrow = 5)) : could not find function "xfun"


foo<-function (x,
     xfun = mean) 
 {
  xfun(x)
 }
 
foo(1:10)
[1] 5.5

what am I missing here?

Thanks

John

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On Apr 1, 2011, at 5:56 PM, array chip wrote:
> Hi, I tried to pass the function dist() as an argument, but got an  
> error
> message. However, almost the same code with mean() as the function  
> to be passed,
> it works ok.
>
> foo<-function (x,
>    xfun = dist)
> {
> xfun(x)
> }
>
> foo(matrix(1:100,nrow=5))
> Error in foo(matrix(1:100, nrow = 5)) : could not find function
"xfun"
>
Works on my machine.

 > foo(matrix(1:100,nrow=5))
           1         2         3         4
2  4.472136
3  8.944272  4.472136
4 13.416408  8.944272  4.472136
5 17.888544 13.416408  8.944272  4.472136


You have probably overwritten `dist` with a non-functional object.

Try rm(dist) and re-run:

>
> foo<-function (x,
>     xfun = mean)
> {
>  xfun(x)
> }
>
> foo(1:10)
> [1] 5.5
>
> what am I missing here?
Thinking about your full workspace, I would guess.

--

David Winsemius, MD
West Hartford, CT

OK, I figured it out, need to add stats::: before dist

foo<-function (x,
    xfun = stats:::dist) 
{
xfun(x)
}


John


________________________________

To: r-help@r-project.org
Sent: Fri, April 1, 2011 2:56:06 PM
Subject: [R] function in argument

Hi, I tried to pass the function dist() as an argument, but got an error 
message. However, almost the same code with mean() as the function to be passed,

it works ok.

foo<-function (x,
    xfun = dist) 
{
xfun(x)
}

foo(matrix(1:100,nrow=5))
Error in foo(matrix(1:100, nrow = 5)) : could not find function "xfun"


foo<-function (x,
     xfun = mean) 
{
  xfun(x)
}

foo(1:10)
[1] 5.5

what am I missing here?

Thanks

John

    [[alternative HTML version deleted]]

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