Dear Thomas,
take a look at setOldClass ...
## register "aov" (an S3-class) as a formally defined class
setOldClass("aov")
## "list" and some others are special cases; cf.
class ? list
## now your code should work
setClassUnion("aovOrNULL", c("aov", "NULL"))
setClass("c1", representation(value = "aovOrNULL"))
y1 <- new("c1", value = NULL)
#trying to assign an aov object to the slot doesn't work
utils::data(npk, package="MASS")
npk.aov <- aov(yield ~ block + N*P*K, npk)
y2 <- new("c1", value = npk.aov )
Best,
Matthias
Thomas Kaliwe wrote:
Dear listmembers,
I would like to define a class with a slot that takes either an object
of class aov or NULL. I have been reading "S4 Classes in 15 pages more
or less" and "Lecture: S4 classes and methods"
#First I tried with list and NULL
setClass(listOrNULL")
setIs("list", "listOrNULL")
setIs("NULL", "listOrNULL")
#doesn't work
#defining a union class it works with list and null
setClassUnion("listOrNULL", c("list", "NULL"))
setClass("c1", representation(value = "listOrNULL"))
y1 = new("c1", value = NULL)
y2 = new("c1", value = list(a = 10))
#but it won't work with aov or null
setClassUnion("aovOrNULL", c("aov", "NULL"))
setClass("c1", representation(value = "aovOrNULL"))
y1 = new("c1", value = NULL)
#trying to assign an aov object to the slot doesn't work
utils::data(npk, package="MASS")
npk.aov <- aov(yield ~ block + N*P*K, npk)
y2 = new("c1", value = npk.aov )
Any ideas?
Thank you
Thomas Kaliwe
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Dr. Matthias Kohl
www.stamats.de
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
