[R] matching values in a list

[dxc13]

That's a very creative way to get the results! I haven't used the "table"
call before, but that certainly made it much easier.  Thanks!


Gabor Grothendieck wrote:
> 
> The first line was missing.  It should be:
> 
> mat <- do.call(rbind, a)
> sapply(apply(mat, 2, table), function(x) mean(as.numeric(names(x))[x
> == length(a)]))
> 
> 
> On Jan 11, 2008 7:23 PM, Gabor Grothendieck <ggrothendieck at gmail.com>
> wrote:
>> Assume that no component matrix can have repeated values.
>>
>> First we apply table to mat yielding a list of named counts.
>> To each component of that we sapply the indicated function
>> which picks out those that occur length(a) times (so they are
>> in every column), converts the name to numeric and averages
>> them.
>>
>> sapply(apply(mat, 2, table), function(x) mean(as.numeric(names(x))[x
>> == length(a)]))
>>
>> By the way, note that the a you define is slightly different from the
>> a displayed in your post.
>>
>>
>> On Jan 11, 2008 6:09 PM, dxc13 <dxc13 at health.state.ny.us> wrote:
>> >
>> > useR's,
>> >
>> > I want to match the real number elements of a list that has 3 matrices
>> as
>> > its elements and then average those numbers.  I think I am close, but I
>> > can't get it to quite work out.  For example,
>> >
>> > > a <- list(matrix(c(10,NA,NA,12,11,
>> > > 10,13,NA,14,12),ncol=2),matrix(c(10,12,15,13,11,
>> > > 13,NA,NA,12,10),ncol=2),matrix(c(10,15,NA,13,NA,
>> 13,12,NA,NA,10),ncol=2))
>> > > a
>> > [[1]]
>> >     [,1] [,2]
>> > [1,]   10   10
>> > [2,]   NA   13
>> > [3,]   NA   NA
>> > [4,]   13   14
>> > [5,]   11   12
>> >
>> > [[2]]
>> >     [,1] [,2]
>> > [1,]   10   13
>> > [2,]   12   NA
>> > [3,]   15   NA
>> > [4,]   13   12
>> > [5,]   11   10
>> >
>> > [[3]]
>> >     [,1] [,2]
>> > [1,]   10   13
>> > [2,]   15   12
>> > [3,]   NA   NA
>> > [4,]   13   NA
>> > [5,]   NA   10
>> >
>> > I want to average the non-NA numbers that simultaneously appear in each
>> > column of all 3 matrices.  For the first column, 10 and 13 are the only
>> > numbers that appear in all 3 matrices.  Thus, I want to take the
>> average of
>> > 10 and 13.  Then repeat the same process for the second column.  The
>> data
>> > here is only a sample, but with the data I work with, there are many
>> more
>> > columns in each matrix in the list.  Does anyone know a efficient way
>> to do
>> > this?  Maybe using lapply()?  Thanks in advance.
>> >
>> > dxc13
>> > --
>> > View this message in context:
>> http://www.nabble.com/matching-values-in-a-list-tp14767170p14767170.html
>> > Sent from the R help mailing list archive at Nabble.com.
>> >
>> > ______________________________________________
>> > R-help at r-project.org 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.
>> >
>>
> 
> ______________________________________________
> R-help at r-project.org 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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