R help - Apr 2018 - How to define mutualy exclusive parameters of a function

Dear All,
apologies if this is basic: I am writing a function:

fb<-function(mean, median, mode, a, b=0.95, lower=F)
{....}

The arguments mean, median and mode are mutually exclusive (i.e. the user
should define only one of these). How do I code this within the function?

Thanks,
Pol

	[[alternative HTML version deleted]]

Hi Pol,
Here is one way:

fb <- function(mean=NULL, median=NULL, mode=NULL, a, b=0.95, lower=F) {

    stopifnot ( (is.null(mean) + is.null(median) + is.null(mode)) == 2 )

    etc...

}


HTH,
Eric


On Thu, Apr 26, 2018 at 4:46 PM, Polychronis Kostoulas <
polychronis.kostoulas at gmail.com> wrote:
> Dear All,
> apologies if this is basic: I am writing a function:
>
> fb<-function(mean, median, mode, a, b=0.95, lower=F)
> {....}
>
> The arguments mean, median and mode are mutually exclusive (i.e. the user
> should define only one of these). How do I code this within the function?
>
> Thanks,
> Pol
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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]]

> On Apr 26, 2018, at 6:46 AM, Polychronis Kostoulas
<polychronis.kostoulas at gmail.com> wrote:
> 
> Dear All,
> apologies if this is basic: I am writing a function:
> 
> fb<-function(mean, median, mode, a, b=0.95, lower=F)
> {....}
> 
> The arguments mean, median and mode are mutually exclusive (i.e. the user
> should define only one of these). How do I code this within the function?
> 
See

?missing

HTH,

Chuck

Hello,

Inline.

On 4/26/2018 5:42 PM, Berry, Charles wrote:
> 
> 
>> On Apr 26, 2018, at 6:46 AM, Polychronis Kostoulas
<polychronis.kostoulas at gmail.com> wrote:
>>
>> Dear All,
>> apologies if this is basic: I am writing a function:
>>
>> fb<-function(mean, median, mode, a, b=0.95, lower=F)
>> {....}
>>
>> The arguments mean, median and mode are mutually exclusive (i.e. the
user
>> should define only one of these). How do I code this within the
function?
>>
> 
> See
> 
> ?missing
See also the first example in help("switch")

Hope this helps,

Rui Barradas

> 
> HTH,
> 
> Chuck
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>