字云-Error (words[i]，cex = size[i]，.)：无效的“cex”值

Question

我正在复制这 word云教程，但我得到：

strwidth中的错误(wordsi，cex = sizei，.)：无效的“cex”值，另外:警告消息: 1: In max(freq)：不缺少参数to max；返回-Inf 2: In max(freq)：不丢失参数给max；返回-Inf

我并不真正理解代码的每一步都发生了什么，但我认为问题可能与生成的具有不同行或列的矩阵有关。这是我正在使用的代码：

install.packages(c("devtools", "rjson", "bit64", "httr"))

library(devtools)
install_github("twitteR", username="geoffjentry")
library(twitteR)

##
api_key= "xxxxxx"
api_secret= "xxxxxx"
access_token="xxxxxxxxxxxx"
access_token_secret= "xxxxxx"
setup_twitter_oauth(api_key,api_secret,access_token,access_token_secret)

searchTwitter("amlo")

library(twitteR)
install.packages("tm")
library(tm)
install.packages("wordcloud")
library(wordcloud)
library(RColorBrewer)

mh370 <- searchTwitter("#PrayForMH370", since = "2014-03-08", until = "2014-03-20", n =             1000)
mh370_text = sapply(mh370, function(x) x$getText())
mh370_corpus = Corpus(VectorSource(mh370_text))

tdm = TermDocumentMatrix(
  mh370_corpus,
  control = list(
    removePunctuation = TRUE,
    stopwords = c("prayformh370", "prayformh", stopwords("english")),
    removeNumbers = TRUE, tolower = TRUE)
)

m = as.matrix(tdm)
# get word counts in decreasing order
word_freqs = sort(rowSums(m), decreasing = TRUE) 
# create a data frame with words and their frequencies
dm = data.frame(word = names(word_freqs), freq = word_freqs)
wordcloud(dm$word, dm$freq, random.order = FALSE, colors = brewer.pal(8, "Dark2"))

Answer 1

问题是tm pacakge中TermDocumentMatrix函数的默认行为是只跟踪比三个字符更长的单词。

因此，只需将这个参数wordLengths=c(0，Inf)添加到TermDocumentMatrix的控制列表中：

tdm = TermDocumentMatrix(
     mh370_corpus,
     control = list(
     wordLengths=c(0,Inf),
     removePunctuation = TRUE,
     stopwords = c("prayformh370", "prayformh", stopwords("english")),
     removeNumbers = TRUE, tolower = TRUE) )