how to use stemDocument in R?

Question

update:

Thanks for help. Check comments. Because of package version, I delete the tolower and it works. I just need to find another way to make it lower.

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Answer 1

This problem appears in tm 0.6 and has to do with using functions that are not in the list of getTransformation() from tm. The problem is that tolower just returns a character vector, and not a "PlainTextDocument" like tm_map would like. The tm packages provides the content_transformer function to take care of managing the PlainTextDocument

fbCorpus  <- tm_map(fbCorpus, content_transformer(tolower))