prose

prose is a natural language processing library (English only, at the moment) in pure Go. It supports tokenization, segmentation, part-of-speech tagging, and named-entity extraction.

You can find a more detailed summary on the library's performance here: Introducing prose v2.0.0: Bringing NLP to Go.

Installation

$ go get github.com/jdkato/prose/v2

Usage

Contents

• Overview
• Tokenizing
• Segmenting
• Tagging
• NER

Overview

package main

import (
    "fmt"
    "log"

    "github.com/jdkato/prose/v2"
)

func main() {
    // Create a new document with the default configuration:
    doc, err := prose.NewDocument("Go is an open-source programming language created at Google.")
    if err != nil {
        log.Fatal(err)
    }

    // Iterate over the doc's tokens:
    for _, tok := range doc.Tokens() {
        fmt.Println(tok.Text, tok.Tag, tok.Label)
        // Go NNP B-GPE
        // is VBZ O
        // an DT O
        // ...
    }

    // Iterate over the doc's named-entities:
    for _, ent := range doc.Entities() {
        fmt.Println(ent.Text, ent.Label)
        // Go GPE
        // Google GPE
    }

    // Iterate over the doc's sentences:
    for _, sent := range doc.Sentences() {
        fmt.Println(sent.Text)
        // Go is an open-source programming language created at Google.
    }
}

The document-creation process adheres to the following sequence of steps:

tokenization -> POS tagging -> NE extraction
            \
             segmentation

Each step may be disabled (assuming later steps aren't required) by passing the appropriate functional option. To disable named-entity extraction, for example, you'd do the following:

doc, err := prose.NewDocument(
        "Go is an open-source programming language created at Google.",
        prose.WithExtraction(false))

Tokenizing

prose includes a tokenizer capable of processing modern text, including the non-word character spans shown below.

package main

import (
    "fmt"
    "log"

    "github.com/jdkato/prose/v2"
)

func main() {
    // Create a new document with the default configuration:
    doc, err := prose.NewDocument("@jdkato, go to http://example.com thanks :).")
    if err != nil {
        log.Fatal(err)
    }

    // Iterate over the doc's tokens:
    for _, tok := range doc.Tokens() {
        fmt.Println(tok.Text, tok.Tag)
        // @jdkato NN
        // , ,
        // go VB
        // to TO
        // http://example.com NN
        // thanks NNS
        // :) SYM
        // . .
    }
}

Segmenting

prose includes one of the most accurate sentence segmenters available, according to the Golden Rules created by the developers of the pragmatic_segmenter.

† The original tests were performed using a MacBook Pro 3.7 GHz Quad-Core Intel Xeon E5 running 10.9.5, while prose was timed using a MacBook Pro 2.9 GHz Intel Core i7 running 10.13.3.

package main

import (
    "fmt"
    "strings"

    "github.com/jdkato/prose/v2"
)

func main() {
    // Create a new document with the default configuration:
    doc, _ := prose.NewDocument(strings.Join([]string{
        "I can see Mt. Fuji from here.",
        "St. Michael's Church is on 5th st. near the light."}, " "))

    // Iterate over the doc's sentences:
    sents := doc.Sentences()
    fmt.Println(len(sents)) // 2
    for _, sent := range sents {
        fmt.Println(sent.Text)
        // I can see Mt. Fuji from here.
        // St. Michael's Church is on 5th st. near the light.
    }
}

Tagging

prose includes a tagger based on Textblob's "fast and accurate" POS tagger. Below is a comparison of its performance against NLTK's implementation of the same tagger on the Treebank corpus:

(See scripts/test_model.py for more information.)

The full list of supported POS tags is given below.

NER

prose v2.0.0 includes a much improved version of v1.0.0's chunk package, which can identify people (PERSON) and geographical/political Entities (GPE) by default.

package main

import (
    "github.com/jdkato/prose/v2"
)

func main() {
    doc, _ := prose.NewDocument("Lebron James plays basketball in Los Angeles.")
    for _, ent := range doc.Entities() {
        fmt.Println(ent.Text, ent.Label)
        // Lebron James PERSON
        // Los Angeles GPE
    }
}

However, in an attempt to make this feature more useful, we've made it straightforward to train your own models for specific use cases. See Prodigy + prose: Radically efficient machine teaching in Go for a tutorial.