[R] NA and NaN question

[Wacek Kusnierczyk]

Wacek Kusnierczyk wrote:
> Pascal A. Niklaus wrote:
>   
>> Hi all,
>>
>> I ran into a problem in some of my code that could be traced back to 'mean' 
>> sometimes returning NA and sometimes NaN, depending on the value of na.rm:
>>
>>   
>>     
>>> mean(c())
>>>     
>>>       
>> [1] NA
>>
>>   
>>     
>>> mean(c(NA),na.rm=T)
>>>     
>>>       
>> [1] NaN
>>
>> However, I don't understand the reasoning behind this and would appreciate and 
>> explanation. 
>>   
>>     
>
> note the types:
>
> typeof(c())
> typeof(c(NA))
> typeof(c(NA)[-na.omit(c(NA))])
>
>   

wrong, an artifact of some experimenting; should have been:

typeof(na.omit(c(NA)))

vQ