CODEWITHSUNDEEP
rtext-mining
Rafael Avila Faraco
Rafael Avila Faraco

Reputation: 11

text mining in R

I would like to create a TDM from a text with specific sentences (two or more words combined) instead of single words. The sentences could be for example "climate change", "global worming", "lad use", etc. The examples I have seen are all with single words.

tabela = DocumentTermMatrix(textolimpo,
         list(dictionary = c("climate change","global worming","land use")))

I appreciate if someone could help me.

Cheers.

Rafael

Upvotes: 1

Views: 94

Answers (1)

lukeA
lukeA

Reputation: 54237

I recommend quanteda: 

library(quanteda)
textolimpo <- c("This climate change concerns me. This climate changes", "Wormed: global worming increased")
(dfm <- dfm(textolimpo, 
           ngrams=2L,
           dictionary = list(climate="climate_change",
                             warm="global_worming"), 
           valuetype = "regex"))
# 2 x 2 sparse Matrix of class "dfmSparse"
#        features
# docs    climate warm
#   text1       2    0
#   text2       0    1
(dfm <- dfm(textolimpo, 
            ngrams=2L, 
            thesaurus = list(climate="climate_change",
                             warm="global_worming"), 
            valuetype = "regex"))
# 2 x 8 sparse Matrix of class "dfmSparse"
#       this_climate change_concerns concerns_me me_this wormed_global worming_increased CLIMATE WARM
# text1            2               1           1       1             0                 0       2    0
# text2            0               0           0       0             1                 1       0    1

Upvotes: 2

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