是什么使这个语料库中的文本小写，我怎样才能把它变成大写？

Question

我正在尝试在R 中构建一个词云，但它只返回小写文本。

sheet <- read_excel('list_products.xls', skip = 4)
products <- c(sheet$Cod)
products <- Corpus(VectorSource(products))
c_words <- brewer.pal(8, 'Set2')
wordcloud(products, min.freq = 10, max.words = 30, scale = c(7,1), colors = c_words)

一旦我尝试将以下代码放在 wordcloud 函数之前，它就不起作用了：

products <- tm_map(products, content_transformer(toupper))

是什么让文本变成小写，我应该怎么做才能把它变成大写？

Answer 1

好吧，正如您从这里看到的：Make all words uppercase in Wordcloud in R，当您执行TermDocumentMatrix(CORPUS) 时，默认情况下单词变为小写。 确实，如果在没有参数freq 的情况下执行trace(wordcloud)，则会执行tdm <- tm::TermDocumentMatrix(corpus)，因此您的单词会变为小写。

您有两种选择来解决这个问题： 包括单词和频率而不是语料库：

filePath <- "http://www.sthda.com/sthda/RDoc/example-files/martin-luther-king-i-have-a-dream-speech.txt" # I am using this text because you DID NOT PROVIDED A REPRODUCIBLE EXAMPLE
text <- readLines(filePath)
products <- Corpus(VectorSource(text))
products <- tm_map(products, toupper)
c_words <- brewer.pal(8, 'Set2')
tdm <- tm::TermDocumentMatrix(products, control = list(tolower = F))
freq_corpus <- slam::row_sums(tdm)
wordcloud(names(freq_corpus), freq_corpus, min.freq = 10, max.words = 30, scale = c(7,1), colors = c_words)

你会得到：

第二个选项是修改wordcloud：

首先你做trace(worcloud, edit=T)，然后将第21行替换为：

tdm <- tm::TermDocumentMatrix(corpus, control = list(tolower = F))

点击保存并执行：

filePath <- "http://www.sthda.com/sthda/RDoc/example-files/martin-luther-king-i-have-a-dream-speech.txt"
text <- readLines(filePath)
products <- Corpus(VectorSource(text))
products <- tm_map(products, toupper)
c_words <- brewer.pal(8, 'Set2')
wordcloud(names(freq_corpus), freq_corpus, min.freq = 10, max.words = 30, scale = c(7,1), colors = c_words)

你会得到类似的东西：