word cloud -Error in strwidth(words[i], cex = size[i], …) : invalid 'cex' value

问题

I am replicating this word cloud tutorial, but I get:

Error in strwidth(words[i], cex = size[i], ...) : invalid 'cex' value In addition: Warning messages: 1: In max(freq) : no non-missing arguments to max; returning -Inf 2: In max(freq) : no non-missing arguments to max; returning -Inf

I do not really understand what is going on on each step of the code, but I think the problem might be related to the matrix produced having different rows or columns. This is the code I am using:

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"))

回答1:

The problem is that the default behavior for the TermDocumentMatrix function from the tm pacakge is that is only tracks words that are longer than three characters.

So just add this parameter wordLengths=c(0,Inf) to the control list of TermDocumentMatrix:

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

来源：https://stackoverflow.com/questions/25113372/word-cloud-error-in-strwidthwordsi-cex-sizei-invalid-cex-valu

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word-cloud