[R] Mean error message missing

[Christian Brandstätter]

Thank you for the explanation.
But if you take for instance plot.default(), being another generic 
function, it would not work like that:
plot(1,2,3,4), only plot(1,2) is accepted.


 From R-help (Usage):
## Default S3 method:
mean(x, trim = 0, na.rm = FALSE, ...)

What is puzzling, is that apparently na.rm (and trim, which is indicated in the help) is accepting numeric values.
mean(c(1,NA,10),10,TRUE)
mean(c(1,NA,10),10,FALSE)

This should give at least a warning in my opinion.

mean(c(1,NA,10),10,200)



On 08/06/2015 09:27, Achim Zeileis wrote:

> On Mon, 8 Jun 2015, Christian Brandstätter wrote:
>
>> Dear list,
>>
>> I found an odd behavior of the mean function; it is allowed to do 
>> something that you probably shouldn't:
>> If you calculate mean() of a sequence of numbers (without declaring 
>> them as vector), mean() then just computes mean() of the first 
>> element. Is there a reason why there is no warning, like in sd for 
>> example?
>
> mean() - unlike sd() - is a generic function that has a '...' argument 
> that is passed on to its methods. The default method which is called 
> in your example also has a '...' argument (because the generic has it) 
> but doesn't use it.
>
>> Example code:
>> mean(1,2,3,4)
>> sd(1,2,3,4)
>>
>> Best regards
>> Christian
>>
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