java - R包中的RWeka错误

Question

我已经搜索过 SO 和其他地方，但没有任何方法可以修复不受支持的 Major.minor 版本 51 错误。我卸载了 Java 8 并安装了 Java 7。没有运气。感谢您的帮助。我在用: R 3.3.1 java 8.91OSX、酋长国图书馆(自然语言处理)图书馆(TM)图书馆(RWeka)库(rJava)图书馆((RWekajars))库(并行)选项(mc.cores=1)这是导致错误的 R 代码:

trigram <- function(x){NGramTokenizer(x,control=Weka_control(min=3,max=3))}
tdm <- TermDocumentMatrix(corpus2,control=list(tokenize=trigram))

Here is the error I get.
 Error in .jnew(name) : 
  java.lang.UnsupportedClassVersionError: weka/core/tokenizers/NGramTokenizer : Unsupported major.minor version 51.0 
9 stop(structure(list(message = "java.lang.UnsupportedClassVersionError: weka/core/tokenizers/NGramTokenizer : Unsupported major.minor version 51.0", 
    call = .jnew(name), jobj = <S4 object of class structure("jobjRef", package = "rJava")>), .Names = c("message", 
"call", "jobj"), class = c("UnsupportedClassVersionError", "ClassFormatError", 
"LinkageError", "Error", "Throwable", "Object", "Exception",  ... 
8 .jnew(name) 
7 NGramTokenizer(x, control = Weka_control(min = 3, max = 3)) 
6 .tokenize(doc) 
5 FUN(X[[i]], ...) 
4 lapply(X = X, FUN = FUN, ...) 
3 mclapply(unname(content(x)), termFreq, control) 
2 TermDocumentMatrix.VCorpus(corpus2, control = list(tokenize = trigram)) 
1 TermDocumentMatrix(corpus2, control = list(tokenize = trigram)) 

Answer 1

我还使用了NGramTokenizer(x, control = Weka_control(min = 3, max = 3))

这给我带来了错误。我遇到了这个分词器，它解决了我的问题。

TrigramTokenizer <-
  function(x)
    unlist(lapply(ngrams(words(x), 3), paste, collapse = " "), use.names = FALSE)

请参阅:https://rpubs.com/hokumski/capstone-milestone-week2欲了解更多信息