[R] create a correct list from Document Term Matrix

[David Winsemius]

> On May 6, 2017, at 7:47 AM, Elahe chalabi via R-help <r-help at r-project.org> wrote:
> 
> Hi all,
> 
> I have a text classification task which is classification of a Control group and Alzheimer group texts. I have generated DocumentTermMatrix for both groups and then created a list with one extra element showing the group name if it's Alzheimer or control group, for example for the Alzheimer group:
> 
> frequenciesAlzheimer=DocumentTermMatrix(corpus)
> freqlistAlz=list(type="alzheimer",frequenciesAlzheimer)
> 
> List of 2
> $ type: chr "alzheimer"
> $        :List of 6    *
> ..$ i      : int [1:8678] 1 1 1 1 1 1 1 1 1 1 ...
> ..$ j      : int [1:8678] 1 2 3 4 5 6 7 8 9 10 ...
> ..$ v      : num [1:8678] 1 1 1 1 1 2 1 1 2 1 ...
> ..$ nrow    : int 255
> ..$ ncol    : int 1091
> ..$ dimnames:List of 2
> .. ..$ Docs : chr [1:255] "1" "2" "3" "4" ...
> .. ..$ Terms: chr [1:1091] "alright" "bad" "boy" "cookie" ...
> ..- attr(*, "class")= chr [1:2] "DocumentTermMatrix" "simple_triplet_matrix"
> ..- attr(*, "weighting")= chr [1:2] "term frequency" "tf"
> 
> and I have the same list for control group,now my question is why I don't get the name of my DTM as the second element of my list? in the line marked by *
> I need to have
> 
> 
> $frequenciesAlzheimer : List of 6
> 
> but there's no name, does anyone know how should I solve this?

Why don't you just assign a name to that list? Either of these should succeed:


names(freqlistAlz)[2] <- frequenciesAlzheimer

freqlistAlz=list(type="alzheimer", 
                   frequenciesAlzheimer =  frequenciesAlzheimer)

-- 
David.


> 
> Thanks for any help!
> Elahe
> 
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David Winsemius
Alameda, CA, USA