2017-05-24 00:16:31 +03:00
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//- 💫 DOCS > USAGE > SPACY 101 > POS TAGGING AND DEPENDENCY PARSING
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p
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| After tokenization, spaCy can also #[strong parse] and #[strong tag] a
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| given #[code Doc]. This is where the statistical model comes in, which
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| enables spaCy to #[strong make a prediction] of which tag or label most
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| likely applies in this context. A model consists of binary data and is
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| produced by showing a system enough examples for it to make predictions
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| that generalise across the language – for example, a word following "the"
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| in English is most likely a noun.
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p
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| Linguistic annotations are available as
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| #[+api("token#attributes") #[code Token] attributes]. Like many NLP
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2017-05-28 20:25:34 +03:00
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| libraries, spaCy #[strong encodes all strings to hash values] to reduce
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2017-05-24 00:16:31 +03:00
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| memory usage and improve efficiency. So to get the readable string
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| representation of an attribute, we need to add an underscore #[code _]
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| to its name:
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+code.
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doc = nlp(u'Apple is looking at buying U.K. startup for $1 billion')
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for token in doc:
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print(token.text, token.lemma_, token.pos_, token.tag_, token.dep_,
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token.shape_, token.is_alpha, token.is_stop)
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+aside
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| #[strong Text:] The original word text.#[br]
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| #[strong Lemma:] The base form of the word.#[br]
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| #[strong POS:] The simple part-of-speech tag.#[br]
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2017-05-25 12:17:21 +03:00
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| #[strong Tag:] The detailed part-of-speech tag.#[br]
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2017-05-24 00:16:31 +03:00
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| #[strong Dep:] Syntactic dependency, i.e. the relation between tokens.#[br]
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| #[strong Shape:] The word shape – capitalisation, punctuation, digits.#[br]
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| #[strong is alpha:] Is the token an alpha character?#[br]
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| #[strong is stop:] Is the token part of a stop list, i.e. the most common
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| words of the language?#[br]
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+table(["Text", "Lemma", "POS", "Tag", "Dep", "Shape", "alpha", "stop"])
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- var style = [0, 0, 1, 1, 1, 1, 1, 1]
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+annotation-row(["Apple", "apple", "PROPN", "NNP", "nsubj", "Xxxxx", true, false], style)
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+annotation-row(["is", "be", "VERB", "VBZ", "aux", "xx", true, true], style)
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+annotation-row(["looking", "look", "VERB", "VBG", "ROOT", "xxxx", true, false], style)
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+annotation-row(["at", "at", "ADP", "IN", "prep", "xx", true, true], style)
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+annotation-row(["buying", "buy", "VERB", "VBG", "pcomp", "xxxx", true, false], style)
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+annotation-row(["U.K.", "u.k.", "PROPN", "NNP", "compound", "X.X.", false, false], style)
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+annotation-row(["startup", "startup", "NOUN", "NN", "dobj", "xxxx", true, false], style)
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+annotation-row(["for", "for", "ADP", "IN", "prep", "xxx", true, true], style)
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+annotation-row(["$", "$", "SYM", "$", "quantmod", "$", false, false], style)
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+annotation-row(["1", "1", "NUM", "CD", "compound", "d", false, false], style)
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+annotation-row(["billion", "billion", "NUM", "CD", "pobj", "xxxx", true, false], style)
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+aside("Tip: Understanding tags and labels")
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| Most of the tags and labels look pretty abstract, and they vary between
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| languages. #[code spacy.explain()] will show you a short description –
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| for example, #[code spacy.explain("VBZ")] returns "verb, 3rd person
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| singular present".
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p
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| Using spaCy's built-in #[+a("/docs/usage/visualizers") displaCy visualizer],
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| here's what our example sentence and its dependencies look like:
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+codepen("030d1e4dfa6256cad8fdd59e6aefecbe", 460)
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