r 中的词干词：缺失值

Question

我正在尝试对推文进行情绪分析。在进行单词预处理和创建矩阵时，出现以下错误：

Error in if (any(lens > lim)) stop("There is a limit of ", lim, "characters on the number of characters in a word being stemmed") : 
missing value where TRUE/FALSE needed

从 14215 条推文中，我将其归结为产生错误的特定推文，但不知道如何防止此错误再次发生。导致错误的推文是（以及重现错误的代码）：

library(RTextTools)
tweet<-"demonio leg edge sexy we get it u vape PLEASE COME TO NA SOON I HAVE A LUCIEL READY FOR U dominos"
all_tweets= create_matrix(tweet, language="english", minWordLength = 3, 
                      removeStopwords=TRUE, removeNumbers=TRUE,  # we can also removeSparseTerms
                      stemWords=TRUE,removePunctuation = TRUE,removeSparseTerms = 0)

我首先想了解这个错误 - 为什么会发生，然后我想要的是一种能够防止这个错误发生的方法 - 通过选择和删除此类推文或编辑我的 create_matrix 以这种方式运行？

Answer 1

错误来自执行

wordStem(
  c("demonio", "leg", "edge", "sexy", 
  "get", "u", "vape", "please", 
  "come", NA, "soon", "luciel", 
  "ready", "u", "dominos")
)
# Error in if (any(lens > lim)) stop("There is a limit of ", lim, "characters on the number of characters in a word being stemmed") : 
#   missing value where TRUE/FALSE needed

也许这是一个错误。字符串 "NA" 似乎被标记化为 NA （缺失值）。

作为解决方法，使用

library(tm)
all_tweets <- DocumentTermMatrix(
  Corpus(VectorSource(tweet)), 
  control = list(
   wordLengths = c(3, Inf), 
   stopwords=TRUE, 
   removeNumbers=TRUE, 
   stemming=TRUE,
   removePunctuation = TRUE
  )
)

我的sessionInfo():

R version 3.3.0 (2016-05-03)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1

locale:
[1] LC_COLLATE=German_Germany.1252  LC_CTYPE=German_Germany.1252    LC_MONETARY=German_Germany.1252
[4] LC_NUMERIC=C                    LC_TIME=German_Germany.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] RTextTools_1.4.2 SparseM_1.7     

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.5         splines_3.3.0       MASS_7.3-44         tau_0.0-18          prodlim_1.5.5       tm_0.6-2           
 [7] lattice_0.20-33     foreach_1.4.3       caTools_1.17.1      tools_3.3.0         nnet_7.3-11         parallel_3.3.0     
[13] grid_3.3.0          ipred_0.9-5         glmnet_2.0-5        e1071_1.6-7         iterators_1.0.8     class_7.3-14       
[19] survival_2.39-4     randomForest_4.6-12 Matrix_1.2-6        NLP_0.1-9           lava_1.4.3          bitops_1.0-6       
[25] codetools_0.2-14    rsconnect_0.4.3     maxent_1.3.3.1      rpart_4.1-10        slam_0.1-32         tree_1.0-36

r 中的词干词：缺失值

Stemming Words in r: Missing Value

twitter

r

stemming