# Apache OpenNLP based POS tag annotators Generate an annotator which computes POS tag annotations using the Apache OpenNLP Maxent Part of Speech tagger. ```r Maxent_POS_Tag_Annotator(language = "en", probs = FALSE, model = NULL) ``` ## Arguments - `language`: a character string giving the ISO-639 code of the language being processed by the annotator. - `probs`: a logical indicating whether the computed annotations should provide the token probabilities obtained from the Maxent model as their POS_prob feature. - `model`: a character string giving the path to the Maxent model file to be used, or `NULL` indicating to use a default model file for the given language (if available, see Details ). ## Returns An `Annotator` object giving the generated POS tag annotator. ## Details See [http://opennlp.sourceforge.net/models-1.5/](http://opennlp.sourceforge.net/models-1.5/) for available model files. For languages other than English, these can conveniently be made available to by installing the respective `openNLPmodels.language` package from the repository at [https://datacube.wu.ac.at](https://datacube.wu.ac.at). For English, no additional installation is required. ## See Also [https://opennlp.apache.org](https://opennlp.apache.org) for more information about Apache OpenNLP. ## Examples ```r require("NLP") ## Some text. s <- paste(c("Pierre Vinken, 61 years old, will join the board as a ", "nonexecutive director Nov. 29.\n", "Mr. Vinken is chairman of Elsevier N.V., ", "the Dutch publishing group."), collapse = "") s <- as.String(s) ## Need sentence and word token annotations. sent_token_annotator <- Maxent_Sent_Token_Annotator() word_token_annotator <- Maxent_Word_Token_Annotator() a2 <- annotate(s, list(sent_token_annotator, word_token_annotator)) pos_tag_annotator <- Maxent_POS_Tag_Annotator() pos_tag_annotator a3 <- annotate(s, pos_tag_annotator, a2) a3 ## Variant with POS tag probabilities as (additional) features. head(annotate(s, Maxent_POS_Tag_Annotator(probs = TRUE), a2)) ## Determine the distribution of POS tags for word tokens. a3w <- subset(a3, type == "word") tags <- sapply(a3w$features, `[[`, "POS") tags table(tags) ## Extract token/POS pairs (all of them): easy. sprintf("%s/%s", s[a3w], tags) ## Extract pairs of word tokens and POS tags for second sentence: a3ws2 <- annotations_in_spans(subset(a3, type == "word"), subset(a3, type == "sentence")[2L])[[1L]] sprintf("%s/%s", s[a3ws2], sapply(a3ws2$features, `[[`, "POS")) ```

Maxent_POS_Tag_Annotator function