From leif at reflectivity.com  Tue Sep 27 20:37:27 2005
From: leif at reflectivity.com (Leif Kirschenbaum)
Date: Tue, 27 Sep 2005 11:37:27 -0700
Subject: [Rd] RODBC and utils:object.size
Message-ID: <200509271837.j8RIbYAN024422@hypatia.math.ethz.ch>

I would like to note that utils::object.size fails on RODBC connection objects.
> DB<-RODBC::odbcConnect("internal")
> utils::object.size(DB)
Error in utils::object.size(DB) : object.size: unknown type 22
> 


I took a brief look at do_objectsize in the source code, and could not figure out how it dealt with new classes of objects. i.e. if someone defines a new class (such as "RODBC") are they supposed to define a size method for the class?


My current workaround for listing object sizes is to drop RODBC objects from Petr Pikal's original ls.objects() function:

ls.objects<-function (pos = 1, order.by,...)
{
    napply <- function(names, fn) sapply(names, function(x) fn(get(x,pos=pos)))
    names <- ls(pos = pos,...)
    obj.class <- napply(names, function(x) as.character(class(x))[1])
    obj.drop <- match("RODBC",obj.class)
    obj.class <- obj.class[-obj.drop]
    names <- names[-obj.drop]
    obj.mode <- napply(names, mode)
    obj.type <- ifelse(is.na(obj.class), obj.mode, obj.class)
    obj.size <- napply(names, object.size)
    obj.dim <- t(napply(names, function(x) as.numeric(dim(x))[1:2]))
    vec <- is.na(obj.dim)[, 1] & (obj.type != "function")
    obj.dim[vec, 1] <- napply(names, length)[vec]
    out <- data.frame(obj.type, obj.size, obj.dim)
    names(out) <- c("Type", "Size", "Rows", "Columns")
    if (!missing(order.by)) out <- out[order(out[[order.by]]), ]
    out
} 



Leif S. Kirschenbaum, Ph.D.
Senior Yield Engineer
Reflectivity, Inc.



[Rd] RODBC and utils:object.size
Leif Kirschenbaum