[Bioc-devel] rbind for ExpressionSet objects?

[Gordon K Smyth]

Hi Martin,

I have only just noticed that the methods package now has generic 
functions rbind2() and cbind2(), which it didn't when the combine() 
function was first created for Biobase.

I think it would be clearer and more elegant to implement rbind2() and 
cbind2() methods for ExpressionSet, and to retire combine() sometime down 
the track (not obviously for the imminent Bioconductor release).  The term 
"combine" is a somewhat overused, e.g., it conflicts with the c() function 
in base.

What do you think?

Cheers
Gordon

On Fri, 4 Apr 2008, Martin Morgan wrote:

> Thanks for the suggestion and examples.
>
> I implemented this in Biobase 1.99.5. It is slightly different from the 
> version in the beadarraySNP package, in that the content of overlapping 
> regions of the exprs arrays have to be identical (beadarraySNP allows NAs in 
> the second matrix).
>
> The functionality I implemented is consistent with the following tests 
> (hopefully self-explanatory).
>
>    data(sample.ExpressionSet)
>    obj <- sample.ExpressionSet
>
>    checkEquals(obj, combine(obj[1:250,], obj[251:500,]))
>    checkEquals(obj, combine(obj[,1:13], obj[,14:26]))
>    ## overlapping
>    checkEquals(obj, combine(obj[1:300,], obj[250:500,]))
>    checkEquals(obj, combine(obj[,1:20], obj[,15:26]))
>
>
> The implementation introduces a combine method for matricies, which is 
> consistent with these tests:
>
>    ## dimnames
>    m <- matrix(1:20, nrow=5, dimnames=list(LETTERS[1:5], letters[1:4]))
>    checkEquals(m, combine(m, m))
>    checkEquals(m, combine(m[1:3,], m[4:5,]))
>    checkEquals(m, combine(m[,1:3], m[,4, drop=FALSE]))
>    ## overlap
>    checkEquals(m, combine(m[1:3,], m[3:5,]))
>    checkEquals(m, combine(m[,1:3], m[,3:4]))
>    checkEquals(matrix(c(1:3, NA, NA, 6:8, NA, NA,
>                         11:15, NA, NA, 18, NA, NA),
>                       nrow=5,
>                       dimnames=list(LETTERS[1:5], letters[1:4])),
>                combine(m[1:3,1:3], m[3:5, 3:4]))
>    ## row reordering
>    checkEquals(m[c(1,3,5,2,4),], combine(m[c(1,3,5),], m[c(2,4),]))
>    ## Exceptions
>    checkException(combine(m, matrix(0, nrow=5, ncol=4)),
>                   silent=TRUE)         # types differ
>    checkException(combine(m, matrix(0L, nrow=5, ncol=4)),
>                   silent=TRUE)         # attributes differ
>    m1 <- matrix(1:20, nrow=5)
>    checkException(combine(m, m1), silent=TRUE) # dimnames required
>
> Please let me know if you had something else in mind, or if there are 
> problems with this.
>
> Martin
>
> Laurent Gautier wrote:
>> That would be useful.
>> 
>> I have been in a situation where it would have been useful, and spent some 
>> time
>> with combine as well before writing my own ad-hoc solution.
>> 
>> 
>> 
>> Laurent
>> 
>> 
>> 2008/4/4, Gordon K Smyth <smyth at wehi.edu.au>:
>>> An rbind() method or an rbind-like function for ExpressionSet objects
>>>  would be useful.  Any plans for such a function?
>>>
>>>  At the moment, an ExpressionSet object can be subsetted by rows or
>>>  columns.  Column subsets can be put back together using combine(), but
>>>  there's no way I think to put row subsets back together.
>>>
>>>  BTW, the help page for the generic function combine() includes the idea 
>>> of
>>>  combining by rows, but this concept is not honoured by the combine method
>>>  for the eSet class.
>>>
>>>  Cheers
>>>  Gordon
>>>
>>>  _______________________________________________
>>>  Bioc-devel at stat.math.ethz.ch mailing list
>>>  https://stat.ethz.ch/mailman/listinfo/bioc-devel
>>> 
>> 
>> 
>
>
> -- 
> Martin Morgan
> Computational Biology / Fred Hutchinson Cancer Research Center
> 1100 Fairview Ave. N.
> PO Box 19024 Seattle, WA 98109
>
> Location: Arnold Building M2 B169
> Phone: (206) 667-2793
>