Re : ReferenceClasses examples {method}
Right. Shame on me : Friday's tiredness ; I don't know why I stuck on that.
Please just consider the main topic of my message, regarding the example of
ReferenceClasses (supposing it's appropriate) and sorry for the subsequent
question...
----- Message d'origine ----
De : David Winsemius <dwinsemius at comcast.net>
? : Marc Carpentier <marc.carpentier at ymail.com>
Cc : r-help at r-project.org
Envoy? le : Ven 28 janvier 2011, 17h 39min 59s
Objet : Re: [R] ReferenceClasses examples {method}
On Jan 28, 2011, at 11:05 AM, Marc Carpentier wrote:
Dear help, dear John Chambers,
I'm trying to learn OOP-possibilities in R and I was going through the
documentation 'ReferenceClasses {methods}'. (great work, by the way...)
Reading associated Examples, something bothers me : it seems to me that there
are errors in 'edit' and 'undo' methods. I think that :
- 'undo' should update 'edits' field with :
length(edits) <<- length(edits) - 1 #(and not - 2)
- and for coherence, 'edit' should store modifications in an 'append'-style :
edits <<- c(edits,list(backup)) #as opposed to c(list(backup),edits)
I hope I'm not wrong.
As a complementary question, suppose one kept 'c(edits,list(backup))', does
anyone know how todiscard first element(s) of a list? For a vector :
vedits<<-vedits[-1]
But lists can't be selected that way ( edits<<- edits [[-1]] #wrong )
You are confusing "[" and "[["
ll <- list(a=1,b=2,cc=3) ll[-1]
$b [1] 2 $cc [1] 3
-- David Winsemius, MD West Hartford, CT