## 21.9 Simple Transforms

We start with some manual special transforms we may want to do. For example, we might want to replace /'', used sometimes to separate alternative words, with a space. This will avoid the two words being run into one string of characters through the transformations. We might also replace@’’ and ’’ with a space, for the same reason.

To create a custom transformation we make use of tm::content_transformer() to create a function to achieve the transformation, and then apply it to the corpus using tm::tm_map().

toSpace <- content_transformer(function(x, pattern) gsub(pattern, " ", x))
docs <- tm_map(docs, toSpace, "/")
docs <- tm_map(docs, toSpace, "@")
docs <- tm_map(docs, toSpace, "\\|")

This can be done with a single call:

docs <- tm_map(docs, toSpace, "/|@|\\|")