From: Doran, Harold <HDoran_at_air.org>

Date: Wed 24 Jan 2007 - 16:15:50 GMT

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Thu Jan 25 15:17:50 2007

Date: Wed 24 Jan 2007 - 16:15:50 GMT

I hadn't thought of that. I use the following at one point in my program

tmp <- with(data, tapply(variable, index, table))

Which returns a list. So, I just went with it for the rest of my program. I'm changing code now to arrays, I think you're right and this may be a better representation. I need to walk through this and see what turns up.

Thanks for the recommendation.

> -----Original Message-----

*> From: Gabor Grothendieck [mailto:ggrothendieck@gmail.com]
**> Sent: Wednesday, January 24, 2007 11:06 AM
**> To: Doran, Harold
**> Cc: r-help@stat.math.ethz.ch
**> Subject: Re: [R] Replace missing values in lapply
**>
**> I wonder if a list of matrices is the best representation?
**> Do your matrices all have the same dimension as in:
**>
**> TP <- list(matrix(c(1:3, NA), 2), matrix(c(NA, 1:3), 2))
**>
**> # Then you could consider representing them as an array:
**>
**> TPa <- array(unlist(TP), c(2,2,2))
**>
**> # in which case its just
**>
**> TPa[is.na(TPa)] <- 0
**> TPa
**>
**>
**> On 1/24/07, Doran, Harold <HDoran@air.org> wrote:
**> > I have some matrices stored as elements in a list that I am working
**> > with. On example is provided below as TP[[18]]
**> >
**> > > TP[[18]]
**> > level2
**> > level1 1 2 3 4
**> > 1 79 0 0 0
**> > 2 0 0 0 0
**> > 3 0 0 0 0
**> > 4 0 0 0 0
**> >
**> > Now, using prop.table on this gives
**> >
**> > > prop.table(TP[[18]],1)
**> > level2
**> > level1 1 2 3 4
**> > 1 1 0 0 0
**> > 2
**> > 3
**> > 4
**> >
**> > It is important for the zero's to retain their position as
**> this matrix
**> > will subsequently be used in some matrix multiplication and hence,
**> > must be of dimension 4 by 4 so that is it conformable for
**> > multiplcation with another matrix.
**> >
**> > In looking at the structure of the object resulting from
**> prop.table I
**> > see NaNs, and so I can do this
**> >
**> > > rr <- TP[[18]]
**> > > rr[is.na(rr)] <- 0
**> > > rr
**> > level2
**> > level1 1 2 3 4
**> > 1 79 0 0 0
**> > 2 0 0 0 0
**> > 3 0 0 0 0
**> > 4 0 0 0 0
**> >
**> > This is exactly what I want for each matrix. But, I have multiple
**> > matrices stored within the list that need to be changed and so I am
**> > trying to resolve this via lapply, but something is awry
**> (namely the
**> > user), but I could use a little help.
**> >
**> > I was thinking the following function should work, but it
**> doesn't. It
**> > reduces each matrix within the list to a 0.
**> >
**> > PP <- lapply(TP, function(x) x[is.na(x)] <- 0)
**> >
**> > Am I missing something obvious?
**> >
**> > Harold
**> >
**> >
**> > [[alternative HTML version deleted]]
**> >
**> > ______________________________________________
**> > R-help@stat.math.ethz.ch mailing list
**> > https://stat.ethz.ch/mailman/listinfo/r-help
**> > PLEASE do read the posting guide
**> > http://www.R-project.org/posting-guide.html
**> > and provide commented, minimal, self-contained, reproducible code.
**> >
*

>

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Thu Jan 25 15:17:50 2007

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