mirror of https://github.com/explosion/spaCy.git
324 lines
15 KiB
Markdown
324 lines
15 KiB
Markdown
---
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title: Vocab
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teaser: A storage class for vocabulary and other data shared across a language
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tag: class
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source: spacy/vocab.pyx
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---
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The `Vocab` object provides a lookup table that allows you to access
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[`Lexeme`](/api/lexeme) objects, as well as the
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[`StringStore`](/api/stringstore). It also owns underlying C-data that is shared
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between `Doc` objects.
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## Vocab.\_\_init\_\_ {#init tag="method"}
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Create the vocabulary.
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> #### Example
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>
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> ```python
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> from spacy.vocab import Vocab
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> vocab = Vocab(strings=["hello", "world"])
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> ```
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| Name | Type | Description |
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| ------------------------------------------- | -------------------- | ------------------------------------------------------------------------------------------------------------------ |
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| `lex_attr_getters` | dict | A dictionary mapping attribute IDs to functions to compute them. Defaults to `None`. |
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| `tag_map` | dict | A dictionary mapping fine-grained tags to coarse-grained parts-of-speech, and optionally morphological attributes. |
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| `lemmatizer` | object | A lemmatizer. Defaults to `None`. |
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| `strings` | `StringStore` / list | A [`StringStore`](/api/stringstore) that maps strings to hash values, and vice versa, or a list of strings. |
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| `vectors_name` <Tag variant="new">2.2</Tag> | unicode | A name to identify the vectors table. |
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| **RETURNS** | `Vocab` | The newly constructed object. |
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## Vocab.\_\_len\_\_ {#len tag="method"}
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Get the current number of lexemes in the vocabulary.
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> #### Example
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>
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> ```python
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> doc = nlp("This is a sentence.")
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> assert len(nlp.vocab) > 0
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> ```
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| Name | Type | Description |
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| ----------- | ---- | ---------------------------------------- |
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| **RETURNS** | int | The number of lexemes in the vocabulary. |
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## Vocab.\_\_getitem\_\_ {#getitem tag="method"}
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Retrieve a lexeme, given an int ID or a unicode string. If a previously unseen
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unicode string is given, a new lexeme is created and stored.
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> #### Example
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>
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> ```python
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> apple = nlp.vocab.strings["apple"]
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> assert nlp.vocab[apple] == nlp.vocab["apple"]
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> ```
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| Name | Type | Description |
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| -------------- | ------------- | ------------------------------------------------ |
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| `id_or_string` | int / unicode | The hash value of a word, or its unicode string. |
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| **RETURNS** | `Lexeme` | The lexeme indicated by the given ID. |
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## Vocab.\_\_iter\_\_ {#iter tag="method"}
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Iterate over the lexemes in the vocabulary.
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> #### Example
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>
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> ```python
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> stop_words = (lex for lex in nlp.vocab if lex.is_stop)
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> ```
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| Name | Type | Description |
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| ---------- | -------- | --------------------------- |
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| **YIELDS** | `Lexeme` | An entry in the vocabulary. |
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## Vocab.\_\_contains\_\_ {#contains tag="method"}
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Check whether the string has an entry in the vocabulary. To get the ID for a
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given string, you need to look it up in
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[`vocab.strings`](/api/vocab#attributes).
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> #### Example
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>
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> ```python
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> apple = nlp.vocab.strings["apple"]
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> oov = nlp.vocab.strings["dskfodkfos"]
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> assert apple in nlp.vocab
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> assert oov not in nlp.vocab
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> ```
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| Name | Type | Description |
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| ----------- | ------- | -------------------------------------------------- |
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| `string` | unicode | The ID string. |
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| **RETURNS** | bool | Whether the string has an entry in the vocabulary. |
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## Vocab.add_flag {#add_flag tag="method"}
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Set a new boolean flag to words in the vocabulary. The `flag_getter` function
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will be called over the words currently in the vocab, and then applied to new
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words as they occur. You'll then be able to access the flag value on each token,
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using `token.check_flag(flag_id)`.
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> #### Example
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>
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> ```python
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> def is_my_product(text):
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> products = ["spaCy", "Thinc", "displaCy"]
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> return text in products
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>
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> MY_PRODUCT = nlp.vocab.add_flag(is_my_product)
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> doc = nlp("I like spaCy")
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> assert doc[2].check_flag(MY_PRODUCT) == True
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> ```
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| Name | Type | Description |
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| ------------- | ---- | ----------------------------------------------------------------------------------------------------------------------------------------------- |
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| `flag_getter` | dict | A function `f(unicode) -> bool`, to get the flag value. |
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| `flag_id` | int | An integer between 1 and 63 (inclusive), specifying the bit at which the flag will be stored. If `-1`, the lowest available bit will be chosen. |
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| **RETURNS** | int | The integer ID by which the flag value can be checked. |
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## Vocab.reset_vectors {#reset_vectors tag="method" new="2"}
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Drop the current vector table. Because all vectors must be the same width, you
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have to call this to change the size of the vectors. Only one of the `width` and
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`shape` keyword arguments can be specified.
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> #### Example
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>
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> ```python
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> nlp.vocab.reset_vectors(width=300)
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> ```
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| Name | Type | Description |
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| ------- | ---- | -------------------------------------- |
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| `width` | int | The new width (keyword argument only). |
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| `shape` | int | The new shape (keyword argument only). |
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## Vocab.prune_vectors {#prune_vectors tag="method" new="2"}
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Reduce the current vector table to `nr_row` unique entries. Words mapped to the
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discarded vectors will be remapped to the closest vector among those remaining.
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For example, suppose the original table had vectors for the words:
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`['sat', 'cat', 'feline', 'reclined']`. If we prune the vector table to, two
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rows, we would discard the vectors for "feline" and "reclined". These words
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would then be remapped to the closest remaining vector – so "feline" would have
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the same vector as "cat", and "reclined" would have the same vector as "sat".
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The similarities are judged by cosine. The original vectors may be large, so the
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cosines are calculated in minibatches, to reduce memory usage.
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> #### Example
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>
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> ```python
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> nlp.vocab.prune_vectors(10000)
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> assert len(nlp.vocab.vectors) <= 1000
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> ```
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| Name | Type | Description |
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| ------------ | ---- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
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| `nr_row` | int | The number of rows to keep in the vector table. |
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| `batch_size` | int | Batch of vectors for calculating the similarities. Larger batch sizes might be faster, while temporarily requiring more memory. |
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| **RETURNS** | dict | A dictionary keyed by removed words mapped to `(string, score)` tuples, where `string` is the entry the removed word was mapped to, and `score` the similarity score between the two words. |
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## Vocab.get_vector {#get_vector tag="method" new="2"}
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Retrieve a vector for a word in the vocabulary. Words can be looked up by string
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or hash value. If no vectors data is loaded, a `ValueError` is raised. If `minn`
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is defined, then the resulting vector uses [FastText](https://fasttext.cc/)'s
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subword features by average over ngrams of `orth` (introduced in spaCy `v2.1`).
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> #### Example
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>
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> ```python
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> nlp.vocab.get_vector("apple")
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> nlp.vocab.get_vector("apple", minn=1, maxn=5)
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> ```
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| Name | Type | Description |
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| ----------------------------------- | ---------------------------------------- | ---------------------------------------------------------------------------------------------- |
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| `orth` | int / unicode | The hash value of a word, or its unicode string. |
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| `minn` <Tag variant="new">2.1</Tag> | int | Minimum n-gram length used for FastText's ngram computation. Defaults to the length of `orth`. |
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| `maxn` <Tag variant="new">2.1</Tag> | int | Maximum n-gram length used for FastText's ngram computation. Defaults to the length of `orth`. |
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| **RETURNS** | `numpy.ndarray[ndim=1, dtype='float32']` | A word vector. Size and shape are determined by the `Vocab.vectors` instance. |
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## Vocab.set_vector {#set_vector tag="method" new="2"}
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Set a vector for a word in the vocabulary. Words can be referenced by by string
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or hash value.
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> #### Example
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>
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> ```python
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> nlp.vocab.set_vector("apple", array([...]))
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> ```
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| Name | Type | Description |
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| -------- | ---------------------------------------- | ------------------------------------------------ |
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| `orth` | int / unicode | The hash value of a word, or its unicode string. |
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| `vector` | `numpy.ndarray[ndim=1, dtype='float32']` | The vector to set. |
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## Vocab.has_vector {#has_vector tag="method" new="2"}
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Check whether a word has a vector. Returns `False` if no vectors are loaded.
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Words can be looked up by string or hash value.
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> #### Example
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>
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> ```python
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> if nlp.vocab.has_vector("apple"):
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> vector = nlp.vocab.get_vector("apple")
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> ```
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| Name | Type | Description |
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| ----------- | ------------- | ------------------------------------------------ |
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| `orth` | int / unicode | The hash value of a word, or its unicode string. |
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| **RETURNS** | bool | Whether the word has a vector. |
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## Vocab.to_disk {#to_disk tag="method" new="2"}
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Save the current state to a directory.
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> #### Example
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>
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> ```python
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> nlp.vocab.to_disk("/path/to/vocab")
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> ```
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| Name | Type | Description |
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| --------- | ---------------- | --------------------------------------------------------------------------------------------------------------------- |
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| `path` | unicode / `Path` | A path to a directory, which will be created if it doesn't exist. Paths may be either strings or `Path`-like objects. |
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| `exclude` | list | String names of [serialization fields](#serialization-fields) to exclude. |
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## Vocab.from_disk {#from_disk tag="method" new="2"}
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Loads state from a directory. Modifies the object in place and returns it.
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> #### Example
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>
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> ```python
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> from spacy.vocab import Vocab
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> vocab = Vocab().from_disk("/path/to/vocab")
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> ```
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| Name | Type | Description |
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| ----------- | ---------------- | -------------------------------------------------------------------------- |
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| `path` | unicode / `Path` | A path to a directory. Paths may be either strings or `Path`-like objects. |
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| `exclude` | list | String names of [serialization fields](#serialization-fields) to exclude. |
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| **RETURNS** | `Vocab` | The modified `Vocab` object. |
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## Vocab.to_bytes {#to_bytes tag="method"}
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Serialize the current state to a binary string.
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> #### Example
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>
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> ```python
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> vocab_bytes = nlp.vocab.to_bytes()
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> ```
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| Name | Type | Description |
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| ----------- | ----- | ------------------------------------------------------------------------- |
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| `exclude` | list | String names of [serialization fields](#serialization-fields) to exclude. |
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| **RETURNS** | bytes | The serialized form of the `Vocab` object. |
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## Vocab.from_bytes {#from_bytes tag="method"}
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Load state from a binary string.
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> #### Example
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>
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> ```python
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> from spacy.vocab import Vocab
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> vocab_bytes = nlp.vocab.to_bytes()
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> vocab = Vocab()
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> vocab.from_bytes(vocab_bytes)
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> ```
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| Name | Type | Description |
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| ------------ | ------- | ------------------------------------------------------------------------- |
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| `bytes_data` | bytes | The data to load from. |
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| `exclude` | list | String names of [serialization fields](#serialization-fields) to exclude. |
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| **RETURNS** | `Vocab` | The `Vocab` object. |
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## Attributes {#attributes}
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> #### Example
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>
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> ```python
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> apple_id = nlp.vocab.strings["apple"]
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> assert type(apple_id) == int
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> PERSON = nlp.vocab.strings["PERSON"]
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> assert type(PERSON) == int
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> ```
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| Name | Type | Description |
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| --------------------------------------------- | ------------- | ------------------------------------------------------------ |
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| `strings` | `StringStore` | A table managing the string-to-int mapping. |
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| `vectors` <Tag variant="new">2</Tag> | `Vectors` | A table associating word IDs to word vectors. |
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| `vectors_length` | int | Number of dimensions for each word vector. |
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| `lookups` | `Lookups` | The available lookup tables in this vocab. |
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| `writing_system` <Tag variant="new">2.1</Tag> | dict | A dict with information about the language's writing system. |
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## Serialization fields {#serialization-fields}
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During serialization, spaCy will export several data fields used to restore
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different aspects of the object. If needed, you can exclude them from
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serialization by passing in the string names via the `exclude` argument.
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> #### Example
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>
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> ```python
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> data = vocab.to_bytes(exclude=["strings", "vectors"])
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> vocab.from_disk("./vocab", exclude=["strings"])
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> ```
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| Name | Description |
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| --------- | ----------------------------------------------------- |
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| `strings` | The strings in the [`StringStore`](/api/stringstore). |
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| `lexemes` | The lexeme data. |
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| `vectors` | The word vectors, if available. |
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| `lookups` | The lookup tables, if available. |
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