创建内容转换器，即用于修改R ..

Question

我的任务是在亚马逊评论的数据集上应用LDA并获得50个主题

我已经在矢量中提取了评论文本，现在我正在尝试应用LDA

我创建了dtm

matrix <- create_matrix(dat, language="english", removeStopwords=TRUE,  stemWords=FALSE, stripWhitespace=TRUE, toLower=TRUE)

<<DocumentTermMatrix (documents: 100000, terms: 174632)>>
Non-/sparse entries: 4096244/17459103756
Sparsity           : 100%
Maximal term length: 218
Weighting          : term frequency (tf)

但是当我尝试这样做时，我收到以下错误：

lda＆lt; - LDA（矩阵，30）

Error in LDA(matrix, 30) : 
  Each row of the input matrix needs to contain at least one non-zero entry

搜索了一些解决方案并使用了大满贯

    matrix1 <- rollup(matrix, 2, na.rm=TRUE, FUN = sum)

仍然得到相同的错误

我是新手，有人可以帮助我或建议我参考研究这个。这将是非常有帮助的

我的原始矩阵中没有空行，它只包含一个包含评论的列

Answer 1

我已被分配了类似的任务，我也在学习和做，我已经有所发展，所以我正在分享我的代码片段，我希望能帮助。

library("topicmodels")
library("tm")

func<-function(input){

x<-c("I like to eat broccoli and bananas.",
        "I ate a banana and spinach smoothie for breakfast.",

"Chinchillas and kittens are cute.",
"My sister adopted a kitten yesterday.",
"Look at this cute hamster munching on a piece of broccoli.")



#whole file is lowercased
#text<-tolower(x)

#deleting all common words from the text
#text2<-setdiff(text,stopwords("english"))

#splitting the text into vectors where each vector is a word..
#text3<-strsplit(text2," ")

# Generating a structured text i.e. Corpus
docs<-Corpus(VectorSource(x))

创建内容转换器，即用于修改R ..

中对象的函数

toSpace <- content_transformer(function (x , pattern ) gsub(pattern, " ", x))

#Removing all the special charecters..

docs <- tm_map(docs, toSpace, "/")
docs <- tm_map(docs, toSpace, "@")
docs <- tm_map(docs, toSpace, "\\|")
docs <- tm_map(docs, removeNumbers)

# Remove english common stopwords
docs <- tm_map(docs, removeWords, stopwords("english"))

# Remove punctuations
docs <- tm_map(docs, removePunctuation)

# Eliminate extra white spaces
docs <- tm_map(docs, stripWhitespace)

docs<-tm_map(docs,removeWords,c("\t"," ",""))

dtm<- TermDocumentMatrix(docs, control = list(removePunctuation = TRUE, stopwords=TRUE))

    #print(dtm)


freq<-colSums(as.matrix(dtm))   

print(names(freq))


ord<-order(freq,decreasing=TRUE)

write.csv(freq[ord],"word_freq.csv")

设置LDA的参数

        burnin<-4000
        iter<-2000
        thin<-500
        seed<-list(2003,5,63,100001,765)
        nstart<-5
        best<-TRUE

        #Number of Topics
        k<-3

# Docs to topics    
    ldaOut<-LDA(dtm,k,method="Gibbs",control=list(nstart=nstart,seed=seed,best=best,burnin=burnin,iter=iter,thin=thin))

    ldaOut.topics<-as.matrix(topics(ldaOut))
    write.csv(ldaOut.topics,file=paste("LDAGibbs",k,"DocsToTopics.csv"))

如何在R中做LDA

1 个答案:

创建内容转换器，即用于修改R ..

设置LDA的参数