[R] how to include 'NA's in xtabs?

[Kosenkov Kirill]

That's ok if i do something like xtabs(~f1). Thanks.
What about xtabs(w~f1+f2)? If i need to do crosstabulation
and factor variables contains NA's?

I want to repeat my second question: how to use 'na.action'
argument in xtabs? Can anybody explain, how is it works?


Petr Pikal wrote:

> Hi
> 
> On 15 May 2003 at 0:18, Kosenkov Kirill wrote:
> 
> 
>>Hello!
>>
>>I have a dataset with NA's in some variables (factors), for example: $
>>P67 : Factor w/ 2 levels "-","+": NA 2 1 NA NA 2 1 1 2 NA ...
>>
>>I need to use 'xtabs' like
>>xtabs(~x$P67)
>>It works well and produces something like this:
>>x$P67
>>    -    +
>>  779 1318
>>but i want to compute NA's too, like this:
>>x$P67
>>    -    +   NA
>>  779 1318  137
> 
> 
> what about using summary instead of xtabs
> 
> 
>>summary(ostbet$delka)
> 
>  159  160 NA's 
>    5   22    3 
> 
> 
>>xtabs(~ostbet$delka)
> 
> ostbet$delka
> 159 160 
>   5  22 
> 
> 
> 
> 
> 
>>I am trying xtabs(~x$P67, exclude=NULL) but xtabs does not compute
>>'NA's in this case too.
>>
>>I do not want to transform my data (do not want to do any 
>>substitution on NA's).
>>
>>How i can say 'xtabs' to compute NA-values?
>>
>>and second question: how to use argument 'na.action' in 'xtabs'?
>>'xtabs' help page does not explain this.
>>
>>Thanks!
>>
>>______________________________________________
>>R-help at stat.math.ethz.ch mailing list
>>https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> 
> 
> Cheers
> Petr Pikal
> petr.pikal at precheza.cz
> p.pik at volny.cz
> 
> 
> 
> 
> .
>