R error with inspect() function

Question

my objective is to apply association rules for text mining.

i have this sample of strings:

sample.word = c("abstracting","abstracting workflow","access control","access information","access methods","access patterns","access permissions","access to government information","accountability","acetamides")

than i make a matrix with all values 0

incidence.matrix_sample <- matrix(0, nrow=5, ncol=length(sample.word))

i add strings as matrix column

colnames(incidence.matrix_sample) <- sample.word

now i put 1 value in the column of terms that appear in document using pmatch function (documents.ids[[i]] is a vector with id of document)

for(i in 1:(dim(incidence.matrix_sample)[1]))
{
  incidence.matrix_sample[i, pmatch(documents.ids[[i]], sample.word)] <- 1
}

i try to go on and transform my matrix first as itemMatrix and then as transactions (with as(my.matrix, "transactions") function) but when i try to inspect rules i get the same error:

incidence.matrix_sample <- as(incidence.matrix_sample, "itemMatrix")
incidence.matrix_sample <- as(incidence.matrix_sample, "transactions")
inspect(incidence.matrix_sample)

the result is:

Errore in UseMethod("inspect", x) : 
  no applicable method for 'inspect' applied to an object of class "c('matrix', 'double', 'numeric')"

and the same problems using apriori function to incidence.matrix_sample

Errore in UseMethod("inspect", x) : 
  no applicable method for 'inspect' applied to an object of class "c('rules', 'associations')"

are days that i'm trying to understand where is the problem.. can someone help me?

Answer 1

The rason of this error is that both arules and tm library has inspect() method and so the order in which they are loaded affects how this method is implemented.

The way to solve this problem is to detach a library before using inspect() method for an object made with other library. For example, after getting incidence matrix i need to detach tm package :

detach(package:tm, unload=TRUE)

then load arules library and use inspect() method for an arules object.

I hope it's useful