spaCy/website/usage/spacy-101.jade

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//- 💫 DOCS > USAGE > SPACY 101
include ../_includes/_mixins
p
| Whether you're new to spaCy, or just want to brush up on some
| NLP basics and implementation details this page should have you covered.
| Each section will explain one of spaCy's features in simple terms and
| with examples or illustrations. Some sections will also reappear across
| the usage guides as a quick introduction.
+aside("Help us improve the docs")
| Did you spot a mistake or come across explanations that
| are unclear? We always appreciate improvement
| #[+a(gh("spaCy") + "/issues") suggestions] or
| #[+a(gh("spaCy") + "/pulls") pull requests]. You can find a "Suggest
| edits" link at the bottom of each page that points you to the source.
+h(2, "whats-spacy") What's spaCy?
+grid.o-no-block
+grid-col("half")
p
| spaCy is a #[strong free, open-source library] for advanced
| #[strong Natural Language Processing] (NLP) in Python.
p
| If you're working with a lot of text, you'll eventually want to
| know more about it. For example, what's it about? What do the
| words mean in context? Who is doing what to whom? What companies
| and products are mentioned? Which texts are similar to each other?
p
| spaCy is designed specifically for #[strong production use] and
| helps you build applications that process and "understand"
| large volumes of text. It can be used to build
| #[strong information extraction] or
| #[strong natural language understanding] systems, or to
| pre-process text for #[strong deep learning].
+table-of-contents
+item #[+a("#features") Features]
+item #[+a("#annotations") Linguistic annotations]
+item #[+a("#annotations-token") Tokenization]
+item #[+a("#annotations-pos-deps") POS tags and dependencies]
+item #[+a("#annotations-ner") Named entities]
+item #[+a("#vectors-similarity") Word vectors and similarity]
+item #[+a("#pipelines") Pipelines]
+item #[+a("#vocab") Vocab, hashes and lexemes]
+item #[+a("#serialization") Serialization]
+item #[+a("#training") Training]
+item #[+a("#language-data") Language data]
+item #[+a("#lightning-tour") Lightning tour]
+item #[+a("#architecture") Architecture]
+item #[+a("#community") Community & FAQ]
+h(3, "what-spacy-isnt") What spaCy isn't
+list
+item #[strong spaCy is not a platform or "an API"].
| Unlike a platform, spaCy does not provide a software as a service, or
| a web application. It's an open-source library designed to help you
| build NLP applications, not a consumable service.
+item #[strong spaCy is not an out-of-the-box chat bot engine].
| While spaCy can be used to power conversational applications, it's
| not designed specifically for chat bots, and only provides the
| underlying text processing capabilities.
+item #[strong spaCy is not research software].
| It's built on the latest research, but it's designed to get
| things done. This leads to fairly different design decisions than
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| #[+a("https://github.com/nltk/nltk") NLTK]
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| or #[+a("https://stanfordnlp.github.io/CoreNLP/") CoreNLP], which were
| created as platforms for teaching and research. The main difference
| is that spaCy is integrated and opinionated. spaCy tries to avoid asking
| the user to choose between multiple algorithms that deliver equivalent
| functionality. Keeping the menu small lets spaCy deliver generally better
| performance and developer experience.
+item #[strong spaCy is not a company].
| It's an open-source library. Our company publishing spaCy and other
| software is called #[+a(COMPANY_URL, true) Explosion AI].
+section("features")
+h(2, "features") Features
p
| In the documentation, you'll come across mentions of spaCy's
| features and capabilities. Some of them refer to linguistic concepts,
| while others are related to more general machine learning
| functionality.
+table(["Name", "Description"])
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+row
+cell #[strong Tokenization]
+cell Segmenting text into words, punctuations marks etc.
+row
+cell #[strong Part-of-speech] (POS) #[strong Tagging]
+cell Assigning word types to tokens, like verb or noun.
+row
+cell #[strong Dependency Parsing]
+cell
| Assigning syntactic dependency labels, describing the
| relations between individual tokens, like subject or object.
+row
+cell #[strong Lemmatization]
+cell
| Assigning the base forms of words. For example, the lemma of
| "was" is "be", and the lemma of "rats" is "rat".
+row
+cell #[strong Sentence Boundary Detection] (SBD)
+cell Finding and segmenting individual sentences.
+row
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+cell #[strong Named Entity Recognition] (NER)
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+cell
| Labelling named "real-world" objects, like persons, companies
| or locations.
+row
+cell #[strong Similarity]
+cell
| Comparing words, text spans and documents and how similar
| they are to each other.
+row
+cell #[strong Text Classification]
+cell
| Assigning categories or labels to a whole document, or parts
| of a document.
+row
+cell #[strong Rule-based Matching]
+cell
| Finding sequences of tokens based on their texts and
| linguistic annotations, similar to regular expressions.
+row
+cell #[strong Training]
+cell Updating and improving a statistical model's predictions.
+row
+cell #[strong Serialization]
+cell Saving objects to files or byte strings.
+h(3, "statistical-models") Statistical models
p
| While some of spaCy's features work independently, others require
| #[+a("/models") statistical models] to be loaded, which enable spaCy
| to #[strong predict] linguistic annotations for example,
| whether a word is a verb or a noun. spaCy currently offers statistical
| models for #[strong #{MODEL_LANG_COUNT} languages], which can be
| installed as individual Python modules. Models can differ in size,
| speed, memory usage, accuracy and the data they include. The model
| you choose always depends on your use case and the texts you're
| working with. For a general-purpose use case, the small, default
| models are always a good start. They typically include the following
| components:
+list
+item
| #[strong Binary weights] for the part-of-speech tagger,
| dependency parser and named entity recognizer to predict those
| annotations in context.
+item
| #[strong Lexical entries] in the vocabulary, i.e. words and their
| context-independent attributes like the shape or spelling.
+item
| #[strong Word vectors], i.e. multi-dimensional meaning
| representations of words that let you determine how similar they
| are to each other.
+item
| #[strong Configuration] options, like the language and
| processing pipeline settings, to put spaCy in the correct state
| when you load in the model.
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+h(2, "annotations") Linguistic annotations
p
| spaCy provides a variety of linguistic annotations to give you
| #[strong insights into a text's grammatical structure]. This
| includes the word types, like the parts of speech, and how the words
| are related to each other. For example, if you're analysing text, it
| makes a huge difference whether a noun is the subject of a sentence,
| or the object or whether "google" is used as a verb, or refers to
| the website or company in a specific context.
+aside-code("Loading models", "bash", "$").
python -m spacy download en
>>> import spacy
>>> nlp = spacy.load('en')
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p
| Once you've #[+a("/usage/models") downloaded and installed] a model,
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| you can load it via #[+api("spacy#load") #[code spacy.load()]]. This will
| return a #[code Language] object contaning all components and data needed
| to process text. We usually call it #[code nlp]. Calling the #[code nlp]
| object on a string of text will return a processed #[code Doc]:
+code.
import spacy
nlp = spacy.load('en')
doc = nlp(u'Apple is looking at buying U.K. startup for $1 billion')
p
| Even though a #[code Doc] is processed e.g. split into individual words
| and annotated it still holds #[strong all information of the original text],
| like whitespace characters. You can always get the offset of a token into the
| original string, or reconstruct the original by joining the tokens and their
| trailing whitespace. This way, you'll never lose any information
| when processing text with spaCy.
+h(3, "annotations-token") Tokenization
include _spacy-101/_tokenization
+infobox
| To learn more about how spaCy's tokenization rules work in detail,
| how to #[strong customise and replace] the default tokenizer and how to
| #[strong add language-specific data], see the usage guides on
| #[+a("/usage/adding-languages") adding languages] and
| #[+a("/usage/linguistic-features#tokenization") customising the tokenizer].
+h(3, "annotations-pos-deps") Part-of-speech tags and dependencies
+tag-model("dependency parse")
include _spacy-101/_pos-deps
+infobox
| To learn more about #[strong part-of-speech tagging] and rule-based
| morphology, and how to #[strong navigate and use the parse tree]
| effectively, see the usage guides on
| #[+a("/usage/linguistic-features#pos-tagging") part-of-speech tagging] and
| #[+a("/usage/linguistic-features#dependency-parse") using the dependency parse].
+h(3, "annotations-ner") Named Entities
+tag-model("named entities")
include _spacy-101/_named-entities
+infobox
| To learn more about entity recognition in spaCy, how to
| #[strong add your own entities] to a document and how to
| #[strong train and update] the entity predictions of a model, see the
| usage guides on
| #[+a("/usage/linguistic-features#named-entities") named entity recognition] and
| #[+a("/usage/training#ner") training the named entity recognizer].
+h(2, "vectors-similarity") Word vectors and similarity
+tag-model("vectors")
include _spacy-101/_similarity
include _spacy-101/_word-vectors
+infobox
| To learn more about word vectors, how to #[strong customise them] and
| how to load #[strong your own vectors] into spaCy, see the usage
| guide on
| #[+a("/usage/vectors-similarity") using word vectors and semantic similarities].
+h(2, "pipelines") Pipelines
include _spacy-101/_pipelines
+infobox
| To learn more about #[strong how processing pipelines work] in detail,
| how to enable and disable their components, and how to
| #[strong create your own], see the usage guide on
| #[+a("/usage/processing-pipelines") language processing pipelines].
+h(2, "vocab") Vocab, hashes and lexemes
include _spacy-101/_vocab
+h(2, "serialization") Serialization
include _spacy-101/_serialization
+infobox
| To learn more about how to #[strong save and load your own models],
| see the usage guide on
| #[+a("/usage/training#saving-loading") saving and loading].
+h(2, "training") Training
include _spacy-101/_training
+infobox
| To learn more about #[strong training and updating] models, how to create
| training data and how to improve spaCy's named entity recognition models,
| see the usage guides on #[+a("/usage/training") training].
+h(2, "language-data") Language data
include _spacy-101/_language-data
+infobox
| To learn more about the individual components of the language data and
| how to #[strong add a new language] to spaCy in preparation for training
| a language model, see the usage guide on
| #[+a("/usage/adding-languages") adding languages].
+section("lightning-tour")
+h(2, "lightning-tour") Lightning tour
include _spacy-101/_lightning-tour
+section("architecture")
+h(2, "architecture") Architecture
include _spacy-101/_architecture
+section("community-faq")
+h(2, "community") Community & FAQ
include _spacy-101/_community-faq