R中的tm_map错误消息

Question

I can create a corpus in R but when I try to apply tm_map functions to it I get the following error message:

Error in UseMethod("as.PlainTextDocument", x) : no applicable method for 'as.PlainTextDocument' applied to an object of class "c('PlainTextDocument', 'TextDocument', 'character')"

The code up to that point is:

setwd("C:/…/Documents/TextMining")
webtextGoogle <- GoogleNewsSource("Greek shipping")
GreekShippingContent <- WebCorpus(GoogleNewsSource("Greek shipping"))
writeCorpus(GreekShippingContent, "C:/…/Documents/TextMining", filenames = paste(seq_along(GreekShippingContent), ".txt", sep=""))
GreekShippingContent0 <- Corpus(DirSource("C:/…/Documents/TextMining"), list(reader = readPlain))
GreekShippingContent2 <- tm_map(GreekShippingContent0, as.PlainTextDocument)

I have looked in the documentation and explanations of what this means in related contexts but I cannot understand what to do (not a developer). Can anyone correct the code? I have learned a lot by example. Thanks.

Answer 1

This is a shot in the dark because you haven't conveyed the problem in a minimal way. I'd suggest to make changes in your question with code tags rather than as comments. This works:

library(tm)

GreekShippingContent <- "The Greek administration is coming under increasing pressure over it foot-dragging regarding its meeting international convention deadlines, especially when it relies on classification societies as an Recognised Organisation (RO) on its behalf. " 
GreekShippingContent0 <-  Corpus(VectorSource(GreekShippingContent))
tm_map(GreekShippingContent0, PlainTextDocument)

You'll have to do some leg work and apply to your situation.