spaCy/website/docs/api/cython-structs.md
Ines Montani e597110d31
💫 Update website (#3285)
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## Description

The new website is implemented using [Gatsby](https://www.gatsbyjs.org) with [Remark](https://github.com/remarkjs/remark) and [MDX](https://mdxjs.com/). This allows authoring content in **straightforward Markdown** without the usual limitations. Standard elements can be overwritten with powerful [React](http://reactjs.org/) components and wherever Markdown syntax isn't enough, JSX components can be used. Hopefully, this update will also make it much easier to contribute to the docs. Once this PR is merged, I'll implement auto-deployment via [Netlify](https://netlify.com) on a specific branch (to avoid building the website on every PR). There's a bunch of other cool stuff that the new setup will allow us to do – including writing front-end tests, service workers, offline support, implementing a search and so on.

This PR also includes various new docs pages and content.
Resolves #3270. Resolves #3222. Resolves #2947. Resolves #2837.


### Types of change
enhancement

## Checklist
<!--- Before you submit the PR, go over this checklist and make sure you can
tick off all the boxes. [] -> [x] -->
- [x] I have submitted the spaCy Contributor Agreement.
- [x] I ran the tests, and all new and existing tests passed.
- [x] My changes don't require a change to the documentation, or if they do, I've added all required information.
2019-02-17 19:31:19 +01:00

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---
title: Cython Structs
teaser: C-language objects that let you group variables together
next: /api/cython-classes
menu:
- ['TokenC', 'tokenc']
- ['LexemeC', 'lexemec']
---
## TokenC {#tokenc tag="C struct" source="spacy/structs.pxd"}
Cython data container for the `Token` object.
> #### Example
>
> ```python
> token = &doc.c[3]
> token_ptr = &doc.c[3]
> ```
| Name | Type | Description |
| ------------ | -------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `lex` | `const LexemeC*` | A pointer to the lexeme for the token. |
| `morph` | `uint64_t` | An ID allowing lookup of morphological attributes. |
| `pos` | `univ_pos_t` | Coarse-grained part-of-speech tag. |
| `spacy` | `bint` | A binary value indicating whether the token has trailing whitespace. |
| `tag` | <Abbr title="uint64_t">`attr_t`</Abbr> | Fine-grained part-of-speech tag. |
| `idx` | `int` | The character offset of the token within the parent document. |
| `lemma` | <Abbr title="uint64_t">`attr_t`</Abbr> | Base form of the token, with no inflectional suffixes. |
| `sense` | <Abbr title="uint64_t">`attr_t`</Abbr> | Space for storing a word sense ID, currently unused. |
| `head` | `int` | Offset of the syntactic parent relative to the token. |
| `dep` | <Abbr title="uint64_t">`attr_t`</Abbr> | Syntactic dependency relation. |
| `l_kids` | `uint32_t` | Number of left children. |
| `r_kids` | `uint32_t` | Number of right children. |
| `l_edge` | `uint32_t` | Offset of the leftmost token of this token's syntactic descendants. |
| `r_edge` | `uint32_t` | Offset of the rightmost token of this token's syntactic descendants. |
| `sent_start` | `int` | Ternary value indicating whether the token is the first word of a sentence. `0` indicates a missing value, `-1` indicates `False` and `1` indicates `True`. The default value, 0, is interpreted as no sentence break. Sentence boundary detectors will usually set 0 for all tokens except tokens that follow a sentence boundary. |
| `ent_iob` | `int` | IOB code of named entity tag. `0` indicates a missing value, `1` indicates `I`, `2` indicates `0` and `3` indicates `B`. |
| `ent_type` | <Abbr title="uint64_t">`attr_t`</Abbr> | Named entity type. |
| `ent_id` | <Abbr title="uint64_t">`attr_t`</Abbr> | ID of the entity the token is an instance of, if any. Currently not used, but potentially for coreference resolution. |
### Token.get_struct_attr {#token_get_struct_attr tag="staticmethod, nogil" source="spacy/tokens/token.pxd"}
Get the value of an attribute from the `TokenC` struct by attribute ID.
> #### Example
>
> ```python
> from spacy.attrs cimport IS_ALPHA
> from spacy.tokens cimport Token
>
> is_alpha = Token.get_struct_attr(&doc.c[3], IS_ALPHA)
> ```
| Name | Type | Description |
| ----------- | -------------------------------------- | -------------------------------------------------------------------------------------- |
| `token` | `const TokenC*` | A pointer to a `TokenC` struct. |
| `feat_name` | `attr_id_t` | The ID of the attribute to look up. The attributes are enumerated in `spacy.typedefs`. |
| **RETURNS** | <Abbr title="uint64_t">`attr_t`</Abbr> | The value of the attribute. |
### Token.set_struct_attr {#token_set_struct_attr tag="staticmethod, nogil" source="spacy/tokens/token.pxd"}
Set the value of an attribute of the `TokenC` struct by attribute ID.
> #### Example
>
> ```python
> from spacy.attrs cimport TAG
> from spacy.tokens cimport Token
>
> token = &doc.c[3]
> Token.set_struct_attr(token, TAG, 0)
> ```
| Name | Type | Description |
| ----------- | -------------------------------------- | -------------------------------------------------------------------------------------- |
| `token` | `const TokenC*` | A pointer to a `TokenC` struct. |
| `feat_name` | `attr_id_t` | The ID of the attribute to look up. The attributes are enumerated in `spacy.typedefs`. |
| `value` | <Abbr title="uint64_t">`attr_t`</Abbr> | The value to set. |
### token_by_start {#token_by_start tag="function" source="spacy/tokens/doc.pxd"}
Find a token in a `TokenC*` array by the offset of its first character.
> #### Example
>
> ```python
> from spacy.tokens.doc cimport Doc, token_by_start
> from spacy.vocab cimport Vocab
>
> doc = Doc(Vocab(), words=[u'hello', u'world'])
> assert token_by_start(doc.c, doc.length, 6) == 1
> assert token_by_start(doc.c, doc.length, 4) == -1
> ```
| Name | Type | Description |
| ------------ | --------------- | --------------------------------------------------------- |
| `tokens` | `const TokenC*` | A `TokenC*` array. |
| `length` | `int` | The number of tokens in the array. |
| `start_char` | `int` | The start index to search for. |
| **RETURNS** | `int` | The index of the token in the array or `-1` if not found. |
### token_by_end {#token_by_end tag="function" source="spacy/tokens/doc.pxd"}
Find a token in a `TokenC*` array by the offset of its final character.
> #### Example
>
> ```python
> from spacy.tokens.doc cimport Doc, token_by_end
> from spacy.vocab cimport Vocab
>
> doc = Doc(Vocab(), words=[u'hello', u'world'])
> assert token_by_end(doc.c, doc.length, 5) == 0
> assert token_by_end(doc.c, doc.length, 1) == -1
> ```
| Name | Type | Description |
| ----------- | --------------- | --------------------------------------------------------- |
| `tokens` | `const TokenC*` | A `TokenC*` array. |
| `length` | `int` | The number of tokens in the array. |
| `end_char` | `int` | The end index to search for. |
| **RETURNS** | `int` | The index of the token in the array or `-1` if not found. |
### set_children_from_heads {#set_children_from_heads tag="function" source="spacy/tokens/doc.pxd"}
Set attributes that allow lookup of syntactic children on a `TokenC*` array.
This function must be called after making changes to the `TokenC.head`
attribute, in order to make the parse tree navigation consistent.
> #### Example
>
> ```python
> from spacy.tokens.doc cimport Doc, set_children_from_heads
> from spacy.vocab cimport Vocab
>
> doc = Doc(Vocab(), words=[u'Baileys', u'from', u'a', u'shoe'])
> doc.c[0].head = 0
> doc.c[1].head = 0
> doc.c[2].head = 3
> doc.c[3].head = 1
> set_children_from_heads(doc.c, doc.length)
> assert doc.c[3].l_kids == 1
> ```
| Name | Type | Description |
| -------- | --------------- | ---------------------------------- |
| `tokens` | `const TokenC*` | A `TokenC*` array. |
| `length` | `int` | The number of tokens in the array. |
## LexemeC {#lexemec tag="C struct" source="spacy/structs.pxd"}
Struct holding information about a lexical type. `LexemeC` structs are usually
owned by the `Vocab`, and accessed through a read-only pointer on the `TokenC`
struct.
> #### Example
>
> ```python
> lex = doc.c[3].lex
> ```
| Name | Type | Description |
| ----------- | --------------------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
| `flags` | <Abbr title="uint64_t">`flags_t`</Abbr> | Bit-field for binary lexical flag values. |
| `id` | <Abbr title="uint64_t">`attr_t`</Abbr> | Usually used to map lexemes to rows in a matrix, e.g. for word vectors. Does not need to be unique, so currently misnamed. |
| `length` | <Abbr title="uint64_t">`attr_t`</Abbr> | Number of unicode characters in the lexeme. |
| `orth` | <Abbr title="uint64_t">`attr_t`</Abbr> | ID of the verbatim text content. |
| `lower` | <Abbr title="uint64_t">`attr_t`</Abbr> | ID of the lowercase form of the lexeme. |
| `norm` | <Abbr title="uint64_t">`attr_t`</Abbr> | ID of the lexeme's norm, i.e. a normalized form of the text. |
| `shape` | <Abbr title="uint64_t">`attr_t`</Abbr> | Transform of the lexeme's string, to show orthographic features. |
| `prefix` | <Abbr title="uint64_t">`attr_t`</Abbr> | Length-N substring from the start of the lexeme. Defaults to `N=1`. |
| `suffix` | <Abbr title="uint64_t">`attr_t`</Abbr> | Length-N substring from the end of the lexeme. Defaults to `N=3`. |
| `cluster` | <Abbr title="uint64_t">`attr_t`</Abbr> | Brown cluster ID. |
| `prob` | `float` | Smoothed log probability estimate of the lexeme's type. |
| `sentiment` | `float` | A scalar value indicating positivity or negativity. |
### Lexeme.get_struct_attr {#lexeme_get_struct_attr tag="staticmethod, nogil" source="spacy/lexeme.pxd"}
Get the value of an attribute from the `LexemeC` struct by attribute ID.
> #### Example
>
> ```python
> from spacy.attrs cimport IS_ALPHA
> from spacy.lexeme cimport Lexeme
>
> lexeme = doc.c[3].lex
> is_alpha = Lexeme.get_struct_attr(lexeme, IS_ALPHA)
> ```
| Name | Type | Description |
| ----------- | -------------------------------------- | -------------------------------------------------------------------------------------- |
| `lex` | `const LexemeC*` | A pointer to a `LexemeC` struct. |
| `feat_name` | `attr_id_t` | The ID of the attribute to look up. The attributes are enumerated in `spacy.typedefs`. |
| **RETURNS** | <Abbr title="uint64_t">`attr_t`</Abbr> | The value of the attribute. |
### Lexeme.set_struct_attr {#lexeme_set_struct_attr tag="staticmethod, nogil" source="spacy/lexeme.pxd"}
Set the value of an attribute of the `LexemeC` struct by attribute ID.
> #### Example
>
> ```python
> from spacy.attrs cimport NORM
> from spacy.lexeme cimport Lexeme
>
> lexeme = doc.c[3].lex
> Lexeme.set_struct_attr(lexeme, NORM, lexeme.lower)
> ```
| Name | Type | Description |
| ----------- | -------------------------------------- | -------------------------------------------------------------------------------------- |
| `lex` | `const LexemeC*` | A pointer to a `LexemeC` struct. |
| `feat_name` | `attr_id_t` | The ID of the attribute to look up. The attributes are enumerated in `spacy.typedefs`. |
| `value` | <Abbr title="uint64_t">`attr_t`</Abbr> | The value to set. |
### Lexeme.c_check_flag {#lexeme_c_check_flag tag="staticmethod, nogil" source="spacy/lexeme.pxd"}
Check the value of a binary flag attribute.
> #### Example
>
> ```python
> from spacy.attrs cimport IS_STOP
> from spacy.lexeme cimport Lexeme
>
> lexeme = doc.c[3].lex
> is_stop = Lexeme.c_check_flag(lexeme, IS_STOP)
> ```
| Name | Type | Description |
| ----------- | ---------------- | ------------------------------------------------------------------------------- |
| `lexeme` | `const LexemeC*` | A pointer to a `LexemeC` struct. |
| `flag_id` | `attr_id_t` | The ID of the flag to look up. The flag IDs are enumerated in `spacy.typedefs`. |
| **RETURNS** | `bint` | The boolean value of the flag. |
### Lexeme.c_set_flag {#lexeme_c_set_flag tag="staticmethod, nogil" source="spacy/lexeme.pxd"}
Set the value of a binary flag attribute.
> #### Example
>
> ```python
> from spacy.attrs cimport IS_STOP
> from spacy.lexeme cimport Lexeme
>
> lexeme = doc.c[3].lex
> Lexeme.c_set_flag(lexeme, IS_STOP, 0)
> ```
| Name | Type | Description |
| --------- | ---------------- | ------------------------------------------------------------------------------- |
| `lexeme` | `const LexemeC*` | A pointer to a `LexemeC` struct. |
| `flag_id` | `attr_id_t` | The ID of the flag to look up. The flag IDs are enumerated in `spacy.typedefs`. |
| `value` | `bint` | The value to set. |