[R] diagnostic information ....

[Jason Turner]

Rolf Turner wrote:

> Paul E. Johnson wrote:
> 
> 
>>I handed out some results from glm() and the students ask "how many 
>>observations were dropped due to missing values"?
>>
>>How would I know? 
...
>  It
> would be ***VERY*** easy to write a wrapper for glm() to include
> the number of dropped observations if you want to include that
> information in a ``printout''.

To wit

naPrint <- function(model,...) {
     if(!inherits(model,"lm") || !inherits(model,"glm"))
         stop("no support for class ",class(model),"\n")
     if(!is.null(model$na.action)) {
         action <- paste("na.action:",attr(model$na.action,"class"))
         rows <- as.numeric(model$na.action)
         list(action=action,rows=rows)
     } else { #no missing values
         list(action=options()$na.action, rows=NULL)
     }
}

Building this as a generic function and its methods is left as an 
exercise ;)  So is a a prettier print method, and possibly a method for 
latex() or xtable().

Cheers

Jason
-- 
Indigo Industrial Controls Ltd.
http://www.indigoindustrial.co.nz
64-21-343-545
jasont at indigoindustrial.co.nz