mirror of
				https://github.com/explosion/spaCy.git
				synced 2025-10-30 23:47:31 +03:00 
			
		
		
		
	* Tidy up pipes * Fix init, defaults and raise custom errors * Update docs * Update docs [ci skip] * Apply suggestions from code review Co-authored-by: Matthew Honnibal <honnibal+gh@gmail.com> * Tidy up error handling and validation, fix consistency * Simplify get_examples check * Remove unused import [ci skip] Co-authored-by: Matthew Honnibal <honnibal+gh@gmail.com>
		
			
				
	
	
		
			1461 lines
		
	
	
		
			65 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			1461 lines
		
	
	
		
			65 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
| ---
 | ||
| title: Language Processing Pipelines
 | ||
| next: /usage/vectors-embeddings
 | ||
| menu:
 | ||
|   - ['Processing Text', 'processing']
 | ||
|   - ['How Pipelines Work', 'pipelines']
 | ||
|   - ['Custom Components', 'custom-components']
 | ||
|   - ['Extension Attributes', 'custom-components-attributes']
 | ||
|   - ['Plugins & Wrappers', 'plugins']
 | ||
| ---
 | ||
| 
 | ||
| import Pipelines101 from 'usage/101/\_pipelines.md'
 | ||
| 
 | ||
| <Pipelines101 />
 | ||
| 
 | ||
| ## Processing text {#processing}
 | ||
| 
 | ||
| When you call `nlp` on a text, spaCy will **tokenize** it and then **call each
 | ||
| component** on the `Doc`, in order. It then returns the processed `Doc` that you
 | ||
| can work with.
 | ||
| 
 | ||
| ```python
 | ||
| doc = nlp("This is a text")
 | ||
| ```
 | ||
| 
 | ||
| When processing large volumes of text, the statistical models are usually more
 | ||
| efficient if you let them work on batches of texts. spaCy's
 | ||
| [`nlp.pipe`](/api/language#pipe) method takes an iterable of texts and yields
 | ||
| processed `Doc` objects. The batching is done internally.
 | ||
| 
 | ||
| ```diff
 | ||
| texts = ["This is a text", "These are lots of texts", "..."]
 | ||
| - docs = [nlp(text) for text in texts]
 | ||
| + docs = list(nlp.pipe(texts))
 | ||
| ```
 | ||
| 
 | ||
| <Infobox title="Tips for efficient processing" emoji="💡">
 | ||
| 
 | ||
| - Process the texts **as a stream** using [`nlp.pipe`](/api/language#pipe) and
 | ||
|   buffer them in batches, instead of one-by-one. This is usually much more
 | ||
|   efficient.
 | ||
| - Only apply the **pipeline components you need**. Getting predictions from the
 | ||
|   model that you don't actually need adds up and becomes very inefficient at
 | ||
|   scale. To prevent this, use the `disable` keyword argument to disable
 | ||
|   components you don't need – either when loading a model, or during processing
 | ||
|   with `nlp.pipe`. See the section on
 | ||
|   [disabling pipeline components](#disabling) for more details and examples.
 | ||
| 
 | ||
| </Infobox>
 | ||
| 
 | ||
| In this example, we're using [`nlp.pipe`](/api/language#pipe) to process a
 | ||
| (potentially very large) iterable of texts as a stream. Because we're only
 | ||
| accessing the named entities in `doc.ents` (set by the `ner` component), we'll
 | ||
| disable all other statistical components (the `tagger` and `parser`) during
 | ||
| processing. `nlp.pipe` yields `Doc` objects, so we can iterate over them and
 | ||
| access the named entity predictions:
 | ||
| 
 | ||
| > #### ✏️ Things to try
 | ||
| >
 | ||
| > 1. Also disable the `"ner"` component. You'll see that the `doc.ents` are now
 | ||
| >    empty, because the entity recognizer didn't run.
 | ||
| 
 | ||
| ```python
 | ||
| ### {executable="true"}
 | ||
| import spacy
 | ||
| 
 | ||
| texts = [
 | ||
|     "Net income was $9.4 million compared to the prior year of $2.7 million.",
 | ||
|     "Revenue exceeded twelve billion dollars, with a loss of $1b.",
 | ||
| ]
 | ||
| 
 | ||
| nlp = spacy.load("en_core_web_sm")
 | ||
| for doc in nlp.pipe(texts, disable=["tagger", "parser"]):
 | ||
|     # Do something with the doc here
 | ||
|     print([(ent.text, ent.label_) for ent in doc.ents])
 | ||
| ```
 | ||
| 
 | ||
| <Infobox title="Important note" variant="warning">
 | ||
| 
 | ||
| When using [`nlp.pipe`](/api/language#pipe), keep in mind that it returns a
 | ||
| [generator](https://realpython.com/introduction-to-python-generators/) that
 | ||
| yields `Doc` objects – not a list. So if you want to use it like a list, you'll
 | ||
| have to call `list()` on it first:
 | ||
| 
 | ||
| ```diff
 | ||
| - docs = nlp.pipe(texts)[0]         # will raise an error
 | ||
| + docs = list(nlp.pipe(texts))[0]   # works as expected
 | ||
| ```
 | ||
| 
 | ||
| </Infobox>
 | ||
| 
 | ||
| ## How pipelines work {#pipelines}
 | ||
| 
 | ||
| spaCy makes it very easy to create your own pipelines consisting of reusable
 | ||
| components – this includes spaCy's default tagger, parser and entity recognizer,
 | ||
| but also your own custom processing functions. A pipeline component can be added
 | ||
| to an already existing `nlp` object, specified when initializing a `Language`
 | ||
| class, or defined within a [model package](/usage/saving-loading#models).
 | ||
| 
 | ||
| > #### config.cfg (excerpt)
 | ||
| >
 | ||
| > ```ini
 | ||
| >  [nlp]
 | ||
| >  lang = "en"
 | ||
| >  pipeline = ["tagger", "parser"]
 | ||
| >
 | ||
| > [components]
 | ||
| >
 | ||
| > [components.tagger]
 | ||
| > factory = "tagger"
 | ||
| > # settings for the tagger component
 | ||
| >
 | ||
| > [components.parser]
 | ||
| > factory = "parser"
 | ||
| > # settings for the parser component
 | ||
| > ```
 | ||
| 
 | ||
| When you load a model, spaCy first consults the model's
 | ||
| [`meta.json`](/usage/saving-loading#models) and
 | ||
| [`config.cfg`](/usage/training#config). The config tells spaCy what language
 | ||
| class to use, which components are in the pipeline, and how those components
 | ||
| should be created. spaCy will then do the following:
 | ||
| 
 | ||
| 1. Load the **language class and data** for the given ID via
 | ||
|    [`get_lang_class`](/api/top-level#util.get_lang_class) and initialize it. The
 | ||
|    `Language` class contains the shared vocabulary, tokenization rules and the
 | ||
|    language-specific settings.
 | ||
| 2. Iterate over the **pipeline names** and look up each component name in the
 | ||
|    `[components]` block. The `factory` tells spaCy which
 | ||
|    [component factory](#custom-components-factories) to use for adding the
 | ||
|    component with with [`add_pipe`](/api/language#add_pipe). The settings are
 | ||
|    passed into the factory.
 | ||
| 3. Make the **model data** available to the `Language` class by calling
 | ||
|    [`from_disk`](/api/language#from_disk) with the path to the model data
 | ||
|    directory.
 | ||
| 
 | ||
| So when you call this...
 | ||
| 
 | ||
| ```python
 | ||
| nlp = spacy.load("en_core_web_sm")
 | ||
| ```
 | ||
| 
 | ||
| ... the model's `config.cfg` tells spaCy to use the language `"en"` and the
 | ||
| pipeline `["tagger", "parser", "ner"]`. spaCy will then initialize
 | ||
| `spacy.lang.en.English`, and create each pipeline component and add it to the
 | ||
| processing pipeline. It'll then load in the model's data from its data directory
 | ||
| and return the modified `Language` class for you to use as the `nlp` object.
 | ||
| 
 | ||
| <Infobox title="Changed in v3.0" variant="warning">
 | ||
| 
 | ||
| spaCy v3.0 introduces a `config.cfg`, which includes more detailed settings for
 | ||
| the model pipeline, its components and the
 | ||
| [training process](/usage/training#config). You can export the config of your
 | ||
| current `nlp` object by calling [`nlp.config.to_disk`](/api/language#config).
 | ||
| 
 | ||
| </Infobox>
 | ||
| 
 | ||
| Fundamentally, a [spaCy model](/models) consists of three components: **the
 | ||
| weights**, i.e. binary data loaded in from a directory, a **pipeline** of
 | ||
| functions called in order, and **language data** like the tokenization rules and
 | ||
| language-specific settings. For example, a Spanish NER model requires different
 | ||
| weights, language data and pipeline components than an English parsing and
 | ||
| tagging model. This is also why the pipeline state is always held by the
 | ||
| `Language` class. [`spacy.load`](/api/top-level#spacy.load) puts this all
 | ||
| together and returns an instance of `Language` with a pipeline set and access to
 | ||
| the binary data:
 | ||
| 
 | ||
| ```python
 | ||
| ### spacy.load under the hood
 | ||
| lang = "en"
 | ||
| pipeline = ["tagger", "parser", "ner"]
 | ||
| data_path = "path/to/en_core_web_sm/en_core_web_sm-2.0.0"
 | ||
| 
 | ||
| cls = spacy.util.get_lang_class(lang)   # 1. Get Language instance, e.g. English()
 | ||
| nlp = cls()                             # 2. Initialize it
 | ||
| for name in pipeline:
 | ||
|     nlp.add_pipe(name)                  # 3. Add the component to the pipeline
 | ||
| nlp.from_disk(model_data_path)          # 4. Load in the binary data
 | ||
| ```
 | ||
| 
 | ||
| When you call `nlp` on a text, spaCy will **tokenize** it and then **call each
 | ||
| component** on the `Doc`, in order. Since the model data is loaded, the
 | ||
| components can access it to assign annotations to the `Doc` object, and
 | ||
| subsequently to the `Token` and `Span` which are only views of the `Doc`, and
 | ||
| don't own any data themselves. All components return the modified document,
 | ||
| which is then processed by the component next in the pipeline.
 | ||
| 
 | ||
| ```python
 | ||
| ### The pipeline under the hood
 | ||
| doc = nlp.make_doc("This is a sentence")   # create a Doc from raw text
 | ||
| for name, proc in nlp.pipeline:             # iterate over components in order
 | ||
|     doc = proc(doc)                         # apply each component
 | ||
| ```
 | ||
| 
 | ||
| The current processing pipeline is available as `nlp.pipeline`, which returns a
 | ||
| list of `(name, component)` tuples, or `nlp.pipe_names`, which only returns a
 | ||
| list of human-readable component names.
 | ||
| 
 | ||
| ```python
 | ||
| print(nlp.pipeline)
 | ||
| # [('tagger', <spacy.pipeline.Tagger>), ('parser', <spacy.pipeline.DependencyParser>), ('ner', <spacy.pipeline.EntityRecognizer>)]
 | ||
| print(nlp.pipe_names)
 | ||
| # ['tagger', 'parser', 'ner']
 | ||
| ```
 | ||
| 
 | ||
| ### Built-in pipeline components {#built-in}
 | ||
| 
 | ||
| spaCy ships with several built-in pipeline components that are registered with
 | ||
| string names. This means that you can initialize them by calling
 | ||
| [`nlp.add_pipe`](/api/language#add_pipe) with their names and spaCy will know
 | ||
| how to create them. See the [API documentation](/api) for a full list of
 | ||
| available pipeline components and component functions.
 | ||
| 
 | ||
| > #### Usage
 | ||
| >
 | ||
| > ```python
 | ||
| > nlp = spacy.blank("en")
 | ||
| > nlp.add_pipe("sentencizer")
 | ||
| > # add_pipe returns the added component
 | ||
| > ruler = nlp.add_pipe("entity_ruler")
 | ||
| > ```
 | ||
| 
 | ||
| | String name     | Component                                       | Description                                                                               |
 | ||
| | --------------- | ----------------------------------------------- | ----------------------------------------------------------------------------------------- |
 | ||
| | `tagger`        | [`Tagger`](/api/tagger)                         | Assign part-of-speech-tags.                                                               |
 | ||
| | `parser`        | [`DependencyParser`](/api/dependencyparser)     | Assign dependency labels.                                                                 |
 | ||
| | `ner`           | [`EntityRecognizer`](/api/entityrecognizer)     | Assign named entities.                                                                    |
 | ||
| | `entity_linker` | [`EntityLinker`](/api/entitylinker)             | Assign knowledge base IDs to named entities. Should be added after the entity recognizer. |
 | ||
| | `entity_ruler`  | [`EntityRuler`](/api/entityruler)               | Assign named entities based on pattern rules and dictionaries.                            |
 | ||
| | `textcat`       | [`TextCategorizer`](/api/textcategorizer)       | Assign text categories.                                                                   |
 | ||
| | `lemmatizer`    | [`Lemmatizer`](/api/lemmatizer)                 | Assign base forms to words.                                                               |
 | ||
| | `morphologizer` | [`Morphologizer`](/api/morphologizer)           | Assign morphological features and coarse-grained POS tags.                                |
 | ||
| | `senter`        | [`SentenceRecognizer`](/api/sentencerecognizer) | Assign sentence boundaries.                                                               |
 | ||
| | `sentencizer`   | [`Sentencizer`](/api/sentencizer)               | Add rule-based sentence segmentation without the dependency parse.                        |
 | ||
| | `tok2vec`       | [`Tok2Vec`](/api/tok2vec)                       |                                                                                           |
 | ||
| | `transformer`   | [`Transformer`](/api/transformer)               | Assign the tokens and outputs of a transformer model.                                     |
 | ||
| 
 | ||
| ### Disabling and modifying pipeline components {#disabling}
 | ||
| 
 | ||
| If you don't need a particular component of the pipeline – for example, the
 | ||
| tagger or the parser, you can **disable loading** it. This can sometimes make a
 | ||
| big difference and improve loading speed. Disabled component names can be
 | ||
| provided to [`spacy.load`](/api/top-level#spacy.load),
 | ||
| [`Language.from_disk`](/api/language#from_disk) or the `nlp` object itself as a
 | ||
| list:
 | ||
| 
 | ||
| ```python
 | ||
| ### Disable loading
 | ||
| nlp = spacy.load("en_core_web_sm", disable=["tagger", "parser"])
 | ||
| ```
 | ||
| 
 | ||
| In some cases, you do want to load all pipeline components and their weights,
 | ||
| because you need them at different points in your application. However, if you
 | ||
| only need a `Doc` object with named entities, there's no need to run all
 | ||
| pipeline components on it – that can potentially make processing much slower.
 | ||
| Instead, you can use the `disable` keyword argument on
 | ||
| [`nlp.pipe`](/api/language#pipe) to temporarily disable the components **during
 | ||
| processing**:
 | ||
| 
 | ||
| ```python
 | ||
| ### Disable for processing
 | ||
| for doc in nlp.pipe(texts, disable=["tagger", "parser"]):
 | ||
|     # Do something with the doc here
 | ||
| ```
 | ||
| 
 | ||
| If you need to **execute more code** with components disabled – e.g. to reset
 | ||
| the weights or update only some components during training – you can use the
 | ||
| [`nlp.select_pipes`](/api/language#select_pipes) contextmanager. At the end of
 | ||
| the `with` block, the disabled pipeline components will be restored
 | ||
| automatically. Alternatively, `select_pipes` returns an object that lets you
 | ||
| call its `restore()` method to restore the disabled components when needed. This
 | ||
| can be useful if you want to prevent unnecessary code indentation of large
 | ||
| blocks.
 | ||
| 
 | ||
| ```python
 | ||
| ### Disable for block
 | ||
| # 1. Use as a contextmanager
 | ||
| with nlp.select_pipes(disable=["tagger", "parser"]):
 | ||
|     doc = nlp("I won't be tagged and parsed")
 | ||
| doc = nlp("I will be tagged and parsed")
 | ||
| 
 | ||
| # 2. Restore manually
 | ||
| disabled = nlp.select_pipes(disable="ner")
 | ||
| doc = nlp("I won't have named entities")
 | ||
| disabled.restore()
 | ||
| ```
 | ||
| 
 | ||
| If you want to disable all pipes except for one or a few, you can use the
 | ||
| `enable` keyword. Just like the `disable` keyword, it takes a list of pipe
 | ||
| names, or a string defining just one pipe.
 | ||
| 
 | ||
| ```python
 | ||
| # Enable only the parser
 | ||
| with nlp.select_pipes(enable="parser"):
 | ||
|     doc = nlp("I will only be parsed")
 | ||
| ```
 | ||
| 
 | ||
| Finally, you can also use the [`remove_pipe`](/api/language#remove_pipe) method
 | ||
| to remove pipeline components from an existing pipeline, the
 | ||
| [`rename_pipe`](/api/language#rename_pipe) method to rename them, or the
 | ||
| [`replace_pipe`](/api/language#replace_pipe) method to replace them with a
 | ||
| custom component entirely (more details on this in the section on
 | ||
| [custom components](#custom-components).
 | ||
| 
 | ||
| ```python
 | ||
| nlp.remove_pipe("parser")
 | ||
| nlp.rename_pipe("ner", "entityrecognizer")
 | ||
| nlp.replace_pipe("tagger", my_custom_tagger)
 | ||
| ```
 | ||
| 
 | ||
| ### Sourcing pipeline components from existing models {#sourced-components new="3"}
 | ||
| 
 | ||
| Pipeline components that are independent can also be reused across models.
 | ||
| Instead of adding a new blank component to a pipeline, you can also copy an
 | ||
| existing component from a pretrained model by setting the `source` argument on
 | ||
| [`nlp.add_pipe`](/api/language#add_pipe). The first argument will then be
 | ||
| interpreted as the name of the component in the source pipeline – for instance,
 | ||
| `"ner"`. This is especially useful for
 | ||
| [training a model](/usage/training#config-components) because it lets you mix
 | ||
| and match components and create fully custom model packages with updated
 | ||
| pretrained components and new components trained on your data.
 | ||
| 
 | ||
| <Infobox variant="warning" title="Important note for pretrained components">
 | ||
| 
 | ||
| When reusing components across models, keep in mind that the **vocabulary**,
 | ||
| **vectors** and model settings **must match**. If a pretrained model includes
 | ||
| [word vectors](/usage/vectors-embeddings) and the component uses them as
 | ||
| features, the model you copy it to needs to have the _same_ vectors available –
 | ||
| otherwise, it won't be able to make the same predictions.
 | ||
| 
 | ||
| </Infobox>
 | ||
| 
 | ||
| > #### In training config
 | ||
| >
 | ||
| > Instead of providing a `factory`, component blocks in the training
 | ||
| > [config](/usage/training#config) can also define a `source`. The string needs
 | ||
| > to be a loadable spaCy model package or path. The
 | ||
| >
 | ||
| > ```ini
 | ||
| > [components.ner]
 | ||
| > source = "en_core_web_sm"
 | ||
| > component = "ner"
 | ||
| > ```
 | ||
| >
 | ||
| > By default, sourced components will be updated with your data during training.
 | ||
| > If you want to preserve the component as-is, you can "freeze" it:
 | ||
| >
 | ||
| > ```ini
 | ||
| > [training]
 | ||
| > frozen_components = ["ner"]
 | ||
| > ```
 | ||
| 
 | ||
| ```python
 | ||
| ### {executable="true"}
 | ||
| import spacy
 | ||
| 
 | ||
| # The source model with different components
 | ||
| source_nlp = spacy.load("en_core_web_sm")
 | ||
| print(source_nlp.pipe_names)
 | ||
| 
 | ||
| # Add only the entity recognizer to the new blank model
 | ||
| nlp = spacy.blank("en")
 | ||
| nlp.add_pipe("ner", source=source_nlp)
 | ||
| print(nlp.pipe_names)
 | ||
| ```
 | ||
| 
 | ||
| ### Analyzing pipeline components {#analysis new="3"}
 | ||
| 
 | ||
| The [`nlp.analyze_pipes`](/api/language#analyze_pipes) method analyzes the
 | ||
| components in the current pipeline and outputs information about them, like the
 | ||
| attributes they set on the [`Doc`](/api/doc) and [`Token`](/api/token), whether
 | ||
| they retokenize the `Doc` and which scores they produce during training. It will
 | ||
| also show warnings if components require values that aren't set by previous
 | ||
| component – for instance, if the entity linker is used but no component that
 | ||
| runs before it sets named entities. Setting `pretty=True` will pretty-print a
 | ||
| table instead of only returning the structured data.
 | ||
| 
 | ||
| > #### ✏️ Things to try
 | ||
| >
 | ||
| > 1. Add the components `"ner"` and `"sentencizer"` _before_ the
 | ||
| >    `"entity_linker"`. The analysis should now show no problems, because
 | ||
| >    requirements are met.
 | ||
| 
 | ||
| ```python
 | ||
| ### {executable="true"}
 | ||
| import spacy
 | ||
| 
 | ||
| nlp = spacy.blank("en")
 | ||
| nlp.add_pipe("tagger")
 | ||
| # This is a problem because it needs entities and sentence boundaries
 | ||
| nlp.add_pipe("entity_linker")
 | ||
| analysis = nlp.analyze_pipes(pretty=True)
 | ||
| ```
 | ||
| 
 | ||
| <Accordion title="Example output">
 | ||
| 
 | ||
| ```json
 | ||
| ### Structured
 | ||
| {
 | ||
|   "summary": {
 | ||
|     "tagger": {
 | ||
|       "assigns": ["token.tag"],
 | ||
|       "requires": [],
 | ||
|       "scores": ["tag_acc", "pos_acc", "lemma_acc"],
 | ||
|       "retokenizes": false
 | ||
|     },
 | ||
|     "entity_linker": {
 | ||
|       "assigns": ["token.ent_kb_id"],
 | ||
|       "requires": ["doc.ents", "doc.sents", "token.ent_iob", "token.ent_type"],
 | ||
|       "scores": [],
 | ||
|       "retokenizes": false
 | ||
|     }
 | ||
|   },
 | ||
|   "problems": {
 | ||
|     "tagger": [],
 | ||
|     "entity_linker": ["doc.ents", "doc.sents", "token.ent_iob", "token.ent_type"]
 | ||
|   },
 | ||
|   "attrs": {
 | ||
|     "token.ent_iob": { "assigns": [], "requires": ["entity_linker"] },
 | ||
|     "doc.ents": { "assigns": [], "requires": ["entity_linker"] },
 | ||
|     "token.ent_kb_id": { "assigns": ["entity_linker"], "requires": [] },
 | ||
|     "doc.sents": { "assigns": [], "requires": ["entity_linker"] },
 | ||
|     "token.tag": { "assigns": ["tagger"], "requires": [] },
 | ||
|     "token.ent_type": { "assigns": [], "requires": ["entity_linker"] }
 | ||
|   }
 | ||
| }
 | ||
| ```
 | ||
| 
 | ||
| ```
 | ||
| ### Pretty
 | ||
| ============================= Pipeline Overview =============================
 | ||
| 
 | ||
| #   Component       Assigns           Requires         Scores      Retokenizes
 | ||
| -   -------------   ---------------   --------------   ---------   -----------
 | ||
| 0   tagger          token.tag                          tag_acc     False
 | ||
|                                                        pos_acc
 | ||
|                                                        lemma_acc
 | ||
| 
 | ||
| 1   entity_linker   token.ent_kb_id   doc.ents                     False
 | ||
|                                       doc.sents
 | ||
|                                       token.ent_iob
 | ||
|                                       token.ent_type
 | ||
| 
 | ||
| 
 | ||
| ================================ Problems (4) ================================
 | ||
| ⚠ 'entity_linker' requirements not met: doc.ents, doc.sents,
 | ||
| token.ent_iob, token.ent_type
 | ||
| ```
 | ||
| 
 | ||
| </Accordion>
 | ||
| 
 | ||
| <Infobox variant="warning" title="Important note">
 | ||
| 
 | ||
| The pipeline analysis is static and does **not actually run the components**.
 | ||
| This means that it relies on the information provided by the components
 | ||
| themselves. If a custom component declares that it assigns an attribute but it
 | ||
| doesn't, the pipeline analysis won't catch that.
 | ||
| 
 | ||
| </Infobox>
 | ||
| 
 | ||
| ## Creating custom pipeline components {#custom-components}
 | ||
| 
 | ||
| A pipeline component is a function that receives a `Doc` object, modifies it and
 | ||
| returns it – – for example, by using the current weights to make a prediction
 | ||
| and set some annotation on the document. By adding a component to the pipeline,
 | ||
| you'll get access to the `Doc` at any point **during processing** – instead of
 | ||
| only being able to modify it afterwards.
 | ||
| 
 | ||
| > #### Example
 | ||
| >
 | ||
| > ```python
 | ||
| > from spacy.language import Language
 | ||
| >
 | ||
| > @Language.component("my_component")
 | ||
| > def my_component(doc):
 | ||
| >    # do something to the doc here
 | ||
| >    return doc
 | ||
| > ```
 | ||
| 
 | ||
| | Argument    | Type  | Description                                            |
 | ||
| | ----------- | ----- | ------------------------------------------------------ |
 | ||
| | `doc`       | `Doc` | The `Doc` object processed by the previous component.  |
 | ||
| | **RETURNS** | `Doc` | The `Doc` object processed by this pipeline component. |
 | ||
| 
 | ||
| The [`@Language.component`](/api/language#component) decorator lets you turn a
 | ||
| simple function into a pipeline component. It takes at least one argument, the
 | ||
| **name** of the component factory. You can use this name to add an instance of
 | ||
| your component to the pipeline. It can also be listed in your model config, so
 | ||
| you can save, load and train models using your component.
 | ||
| 
 | ||
| Custom components can be added to the pipeline using the
 | ||
| [`add_pipe`](/api/language#add_pipe) method. Optionally, you can either specify
 | ||
| a component to add it **before or after**, tell spaCy to add it **first or
 | ||
| last** in the pipeline, or define a **custom name**. If no name is set and no
 | ||
| `name` attribute is present on your component, the function name is used.
 | ||
| 
 | ||
| > #### Example
 | ||
| >
 | ||
| > ```python
 | ||
| > nlp.add_pipe("my_component")
 | ||
| > nlp.add_pipe("my_component", first=True)
 | ||
| > nlp.add_pipe("my_component", before="parser")
 | ||
| > ```
 | ||
| 
 | ||
| | Argument | Type      | Description                                                              |
 | ||
| | -------- | --------- | ------------------------------------------------------------------------ |
 | ||
| | `last`   | bool      | If set to `True`, component is added **last** in the pipeline (default). |
 | ||
| | `first`  | bool      | If set to `True`, component is added **first** in the pipeline.          |
 | ||
| | `before` | str / int | String name or index to add the new component **before**.                |
 | ||
| | `after`  | str / int | String name or index to add the new component **after**.                 |
 | ||
| 
 | ||
| <Infobox title="Changed in v3.0" variant="warning">
 | ||
| 
 | ||
| As of v3.0, components need to be registered using the
 | ||
| [`@Language.component`](/api/language#component) or
 | ||
| [`@Language.factory`](/api/language#factory) decorator so spaCy knows that a
 | ||
| function is a component. [`nlp.add_pipe`](/api/language#add_pipe) now takes the
 | ||
| **string name** of the component factory instead of the component function. This
 | ||
| doesn't only save you lines of code, it also allows spaCy to validate and track
 | ||
| your custom components, and make sure they can be saved and loaded.
 | ||
| 
 | ||
| ```diff
 | ||
| - ruler = nlp.create_pipe("entity_ruler")
 | ||
| - nlp.add_pipe(ruler)
 | ||
| + ruler = nlp.add_pipe("entity_ruler")
 | ||
| ```
 | ||
| 
 | ||
| </Infobox>
 | ||
| 
 | ||
| ### Examples: Simple stateless pipeline components {#custom-components-simple}
 | ||
| 
 | ||
| The following component receives the `Doc` in the pipeline and prints some
 | ||
| information about it: the number of tokens, the part-of-speech tags of the
 | ||
| tokens and a conditional message based on the document length. The
 | ||
| [`@Language.component`](/api/language#component) decorator lets you register the
 | ||
| component under the name `"info_component"`.
 | ||
| 
 | ||
| > #### ✏️ Things to try
 | ||
| >
 | ||
| > 1. Add the component first in the pipeline by setting `first=True`. You'll see
 | ||
| >    that the part-of-speech tags are empty, because the component now runs
 | ||
| >    before the tagger and the tags aren't available yet.
 | ||
| > 2. Change the component `name` or remove the `name` argument. You should see
 | ||
| >    this change reflected in `nlp.pipe_names`.
 | ||
| > 3. Print `nlp.pipeline`. You'll see a list of tuples describing the component
 | ||
| >    name and the function that's called on the `Doc` object in the pipeline.
 | ||
| > 4. Change the first argument to `@Language.component`, the name, to something
 | ||
| >    else. spaCy should now complain that it doesn't know a component of the
 | ||
| >    name `"info_component"`.
 | ||
| 
 | ||
| ```python
 | ||
| ### {executable="true"}
 | ||
| import spacy
 | ||
| from spacy.language import Language
 | ||
| 
 | ||
| @Language.component("info_component")
 | ||
| def my_component(doc):
 | ||
|     print(f"After tokenization, this doc has {len(doc)} tokens.")
 | ||
|     print("The part-of-speech tags are:", [token.pos_ for token in doc])
 | ||
|     if len(doc) < 10:
 | ||
|         print("This is a pretty short document.")
 | ||
|     return doc
 | ||
| 
 | ||
| nlp = spacy.load("en_core_web_sm")
 | ||
| nlp.add_pipe("info_component", name="print_info", last=True)
 | ||
| print(nlp.pipe_names)  # ['tagger', 'parser', 'ner', 'print_info']
 | ||
| doc = nlp("This is a sentence.")
 | ||
| ```
 | ||
| 
 | ||
| Here's another example of a pipeline component that implements custom logic to
 | ||
| improve the sentence boundaries set by the dependency parser. The custom logic
 | ||
| should therefore be applied **after** tokenization, but _before_ the dependency
 | ||
| parsing – this way, the parser can also take advantage of the sentence
 | ||
| boundaries.
 | ||
| 
 | ||
| > #### ✏️ Things to try
 | ||
| >
 | ||
| > 1. Print `[token.dep_ for token in doc]` with and without the custom pipeline
 | ||
| >    component. You'll see that the predicted dependency parse changes to match
 | ||
| >    the sentence boundaries.
 | ||
| > 2. Remove the `else` block. All other tokens will now have `is_sent_start` set
 | ||
| >    to `None` (missing value), the parser will assign sentence boundaries in
 | ||
| >    between.
 | ||
| 
 | ||
| ```python
 | ||
| ### {executable="true"}
 | ||
| import spacy
 | ||
| from spacy.language import Language
 | ||
| 
 | ||
| @Language.component("custom_sentencizer")
 | ||
| def custom_sentencizer(doc):
 | ||
|     for i, token in enumerate(doc[:-2]):
 | ||
|         # Define sentence start if pipe + titlecase token
 | ||
|         if token.text == "|" and doc[i + 1].is_title:
 | ||
|             doc[i + 1].is_sent_start = True
 | ||
|         else:
 | ||
|             # Explicitly set sentence start to False otherwise, to tell
 | ||
|             # the parser to leave those tokens alone
 | ||
|             doc[i + 1].is_sent_start = False
 | ||
|     return doc
 | ||
| 
 | ||
| nlp = spacy.load("en_core_web_sm")
 | ||
| nlp.add_pipe("custom_sentencizer", before="parser")  # Insert before the parser
 | ||
| doc = nlp("This is. A sentence. | This is. Another sentence.")
 | ||
| for sent in doc.sents:
 | ||
|     print(sent.text)
 | ||
| ```
 | ||
| 
 | ||
| ### Component factories and stateful components {#custom-components-factories}
 | ||
| 
 | ||
| Component factories are callables that take settings and return a **pipeline
 | ||
| component function**. This is useful if your component is stateful and if you
 | ||
| need to customize their creation, or if you need access to the current `nlp`
 | ||
| object or the shared vocab. Component factories can be registered using the
 | ||
| [`@Language.factory`](/api/language#factory) decorator and they need at least
 | ||
| **two named arguments** that are filled in automatically when the component is
 | ||
| added to the pipeline:
 | ||
| 
 | ||
| > #### Example
 | ||
| >
 | ||
| > ```python
 | ||
| > from spacy.language import Language
 | ||
| >
 | ||
| > @Language.factory("my_component")
 | ||
| > def my_component(nlp, name):
 | ||
| >    return MyComponent()
 | ||
| > ```
 | ||
| 
 | ||
| | Argument | Type                        | Description                                                                                                               |
 | ||
| | -------- | --------------------------- | ------------------------------------------------------------------------------------------------------------------------- |
 | ||
| | `nlp`    | [`Language`](/api/language) | The current `nlp` object. Can be used to access the                                                                       |
 | ||
| | `name`   | str                         | The **instance name** of the component in the pipeline. This lets you identify different instances of the same component. |
 | ||
| 
 | ||
| All other settings can be passed in by the user via the `config` argument on
 | ||
| [`nlp.add_pipe`](/api/language). The
 | ||
| [`@Language.factory`](/api/language#factory) decorator also lets you define a
 | ||
| `default_config` that's used as a fallback.
 | ||
| 
 | ||
| <!-- TODO: add example of passing in a custom Python object via the config based on a registered function -->
 | ||
| 
 | ||
| ```python
 | ||
| ### With config {highlight="4,9"}
 | ||
| import spacy
 | ||
| from spacy.language import Language
 | ||
| 
 | ||
| @Language.factory("my_component", default_config={"some_setting": True})
 | ||
| def my_component(nlp, name, some_setting: bool):
 | ||
|     return MyComponent(some_setting=some_setting)
 | ||
| 
 | ||
| nlp = spacy.blank("en")
 | ||
| nlp.add_pipe("my_component", config={"some_setting": False})
 | ||
| ```
 | ||
| 
 | ||
| <Accordion title="How is @Language.factory different from @Language.component?" id="factories-decorator-component">
 | ||
| 
 | ||
| The [`@Language.component`](/api/language#component) decorator is essentially a
 | ||
| **shortcut** for stateless pipeline component that don't need any settings. This
 | ||
| means you don't have to always write a function that returns your function if
 | ||
| there's no state to be passed through – spaCy can just take care of this for
 | ||
| you. The following two code examples are equivalent:
 | ||
| 
 | ||
| ```python
 | ||
| # Statless component with @Language.factory
 | ||
| @Language.factory("my_component")
 | ||
| def create_my_component():
 | ||
|     def my_component(doc):
 | ||
|         # Do something to the doc
 | ||
|         return doc
 | ||
| 
 | ||
|     return my_component
 | ||
| 
 | ||
| # Stateless component with @Language.component
 | ||
| @Language.component("my_component")
 | ||
| def my_component(doc):
 | ||
|     # Do something to the doc
 | ||
|     return doc
 | ||
| ```
 | ||
| 
 | ||
| </Accordion>
 | ||
| 
 | ||
| <Accordion title="Can I add the @Language.factory decorator to a class?" id="factories-class-decorator" spaced>
 | ||
| 
 | ||
| Yes, the [`@Language.factory`](/api/language#factory) decorator can be added to
 | ||
| a function or a class. If it's added to a class, it expects the `__init__`
 | ||
| method to take the arguments `nlp` and `name`, and will populate all other
 | ||
| arguments from the config. That said, it's often cleaner and more intuitive to
 | ||
| make your factory a separate function. That's also how spaCy does it internally.
 | ||
| 
 | ||
| </Accordion>
 | ||
| 
 | ||
| ### Example: Stateful component with settings
 | ||
| 
 | ||
| This example shows a **stateful** pipeline component for handling acronyms:
 | ||
| based on a dictionary, it will detect acronyms and their expanded forms in both
 | ||
| directions and add them to a list as the custom `doc._.acronyms`
 | ||
| [extension attribute](#custom-components-attributes). Under the hood, it uses
 | ||
| the [`PhraseMatcher`](/api/phrasematcher) to find instances of the phrases.
 | ||
| 
 | ||
| The factory function takes three arguments: the shared `nlp` object and
 | ||
| component instance `name`, which are passed in automatically by spaCy, and a
 | ||
| `case_sensitive` config setting that makes the matching and acronym detection
 | ||
| case-sensitive.
 | ||
| 
 | ||
| > #### ✏️ Things to try
 | ||
| >
 | ||
| > 1. Change the `config` passed to `nlp.add_pipe` and set `"case_sensitive"` to
 | ||
| >    `True`. You should see that the expanded acronym for "LOL" isn't detected
 | ||
| >    anymore.
 | ||
| > 2. Add some more terms to the `DICTIONARY` and update the processed text so
 | ||
| >    they're detected.
 | ||
| > 3. Add a `name` argument to `nlp.add_pipe` to change the component name. Print
 | ||
| >    `nlp.pipe_names` to see the change reflected in the pipeline.
 | ||
| > 4. Print the config of the current `nlp` object with
 | ||
| >    `print(nlp.config.to_str())` and inspect the `[components]` block. You
 | ||
| >    should see an entry for the acronyms component, referencing the factory
 | ||
| >    `acronyms` and the config settings.
 | ||
| 
 | ||
| ```python
 | ||
| ### {executable="true"}
 | ||
| from spacy.language import Language
 | ||
| from spacy.tokens import Doc
 | ||
| from spacy.matcher import PhraseMatcher
 | ||
| import spacy
 | ||
| 
 | ||
| DICTIONARY = {"lol": "laughing out loud", "brb": "be right back"}
 | ||
| DICTIONARY.update({value: key for key, value in DICTIONARY.items()})
 | ||
| 
 | ||
| @Language.factory("acronyms", default_config={"case_sensitive": False})
 | ||
| def create_acronym_component(nlp: Language, name: str, case_sensitive: bool):
 | ||
|     return AcronymComponent(nlp, case_sensitive)
 | ||
| 
 | ||
| class AcronymComponent:
 | ||
|     def __init__(self, nlp: Language, case_sensitive: bool):
 | ||
|         # Create the matcher and match on Token.lower if case-insensitive
 | ||
|         matcher_attr = "TEXT" if case_sensitive else "LOWER"
 | ||
|         self.matcher = PhraseMatcher(nlp.vocab, attr=matcher_attr)
 | ||
|         self.matcher.add("ACRONYMS", [nlp.make_doc(term) for term in DICTIONARY])
 | ||
|         self.case_sensitive = case_sensitive
 | ||
|         # Register custom extension on the Doc
 | ||
|         if not Doc.has_extension("acronyms"):
 | ||
|             Doc.set_extension("acronyms", default=[])
 | ||
| 
 | ||
|     def __call__(self, doc: Doc) -> Doc:
 | ||
|         # Add the matched spans when doc is processed
 | ||
|         for _, start, end in self.matcher(doc):
 | ||
|             span = doc[start:end]
 | ||
|             acronym = DICTIONARY.get(span.text if self.case_sensitive else span.text.lower())
 | ||
|             doc._.acronyms.append((span, acronym))
 | ||
|         return doc
 | ||
| 
 | ||
| # Add the component to the pipeline and configure it
 | ||
| nlp = spacy.blank("en")
 | ||
| nlp.add_pipe("acronyms", config={"case_sensitive": False})
 | ||
| 
 | ||
| # Process a doc and see the results
 | ||
| doc = nlp("LOL, be right back")
 | ||
| print(doc._.acronyms)
 | ||
| ```
 | ||
| 
 | ||
| ### Python type hints and pydantic validation {#type-hints new="3"}
 | ||
| 
 | ||
| spaCy's configs are powered by our machine learning library Thinc's
 | ||
| [configuration system](https://thinc.ai/docs/usage-config), which supports
 | ||
| [type hints](https://docs.python.org/3/library/typing.html) and even
 | ||
| [advanced type annotations](https://thinc.ai/docs/usage-config#advanced-types)
 | ||
| using [`pydantic`](https://github.com/samuelcolvin/pydantic). If your component
 | ||
| factory provides type hints, the values that are passed in will be **checked
 | ||
| against the expected types**. If the value can't be cast to an integer, spaCy
 | ||
| will raise an error. `pydantic` also provides strict types like `StrictFloat`,
 | ||
| which will force the value to be an integer and raise an error if it's not – for
 | ||
| instance, if your config defines a float.
 | ||
| 
 | ||
| <Infobox variant="warning">
 | ||
| 
 | ||
| If you're not using
 | ||
| [strict types](https://pydantic-docs.helpmanual.io/usage/types/#strict-types),
 | ||
| values that can be **cast to** the given type will still be accepted. For
 | ||
| example, `1` can be cast to a `float` or a `bool` type, but not to a
 | ||
| `List[str]`. However, if the type is
 | ||
| [`StrictFloat`](https://pydantic-docs.helpmanual.io/usage/types/#strict-types),
 | ||
| only a float will be accepted.
 | ||
| 
 | ||
| </Infobox>
 | ||
| 
 | ||
| The following example shows a custom pipeline component for debugging. It can be
 | ||
| added anywhere in the pipeline and logs information about the `nlp` object and
 | ||
| the `Doc` that passes through. The `log_level` config setting lets the user
 | ||
| customize what log statements are shown – for instance, `"INFO"` will show info
 | ||
| logs and more critical logging statements, whereas `"DEBUG"` will show
 | ||
| everything. The value is annotated as a `StrictStr`, so it will only accept a
 | ||
| string value.
 | ||
| 
 | ||
| > #### ✏️ Things to try
 | ||
| >
 | ||
| > 1. Change the `config` passed to `nlp.add_pipe` to use the log level `"INFO"`.
 | ||
| >    You should see that only the statement logged with `logger.info` is shown.
 | ||
| > 2. Change the `config` passed to `nlp.add_pipe` so that it contains unexpected
 | ||
| >    values – for example, a boolean instead of a string: `"log_level": False`.
 | ||
| >    You should see a validation error.
 | ||
| > 3. Check out the docs on `pydantic`'s
 | ||
| >    [constrained types](https://pydantic-docs.helpmanual.io/usage/types/#constrained-types)
 | ||
| >    and write a type hint for `log_level` that only accepts the exact string
 | ||
| >    values `"DEBUG"`, `"INFO"` or `"CRITICAL"`.
 | ||
| 
 | ||
| ```python
 | ||
| ### {executable="true"}
 | ||
| import spacy
 | ||
| from spacy.language import Language
 | ||
| from spacy.tokens import Doc
 | ||
| from pydantic import StrictStr
 | ||
| import logging
 | ||
| 
 | ||
| @Language.factory("debug", default_config={"log_level": "DEBUG"})
 | ||
| class DebugComponent:
 | ||
|     def __init__(self, nlp: Language, name: str, log_level: StrictStr):
 | ||
|         self.logger = logging.getLogger(f"spacy.{name}")
 | ||
|         self.logger.setLevel(log_level)
 | ||
|         self.logger.info(f"Pipeline: {nlp.pipe_names}")
 | ||
| 
 | ||
|     def __call__(self, doc: Doc) -> Doc:
 | ||
|         self.logger.debug(f"Doc: {len(doc)} tokens, is_tagged: {doc.is_tagged}")
 | ||
|         return doc
 | ||
| 
 | ||
| nlp = spacy.load("en_core_web_sm")
 | ||
| nlp.add_pipe("debug", config={"log_level": "DEBUG"})
 | ||
| doc = nlp("This is a text...")
 | ||
| ```
 | ||
| 
 | ||
| ### Language-specific factories {#factories-language new="3"}
 | ||
| 
 | ||
| There are many use case where you might want your pipeline components to be
 | ||
| language-specific. Sometimes this requires entirely different implementation per
 | ||
| language, sometimes the only difference is in the settings or data. spaCy allows
 | ||
| you to register factories of the **same name** on both the `Language` base
 | ||
| class, as well as its **subclasses** like `English` or `German`. Factories are
 | ||
| resolved starting with the specific subclass. If the subclass doesn't define a
 | ||
| component of that name, spaCy will check the `Language` base class.
 | ||
| 
 | ||
| Here's an example of a pipeline component that overwrites the normalized form of
 | ||
| a token, the `Token.norm_` with an entry from a language-specific lookup table.
 | ||
| It's registered twice under the name `"token_normalizer"` – once using
 | ||
| `@English.factory` and once using `@German.factory`:
 | ||
| 
 | ||
| ```python
 | ||
| ### {executable="true"}
 | ||
| from spacy.lang.en import English
 | ||
| from spacy.lang.de import German
 | ||
| 
 | ||
| class TokenNormalizer:
 | ||
|     def __init__(self, norm_table):
 | ||
|         self.norm_table = norm_table
 | ||
| 
 | ||
|     def __call__(self, doc):
 | ||
|         for token in doc:
 | ||
|             # Overwrite the token.norm_ if there's an entry in the data
 | ||
|             token.norm_ = self.norm_table.get(token.text, token.norm_)
 | ||
|         return doc
 | ||
| 
 | ||
| @English.factory("token_normalizer")
 | ||
| def create_en_normalizer(nlp, name):
 | ||
|     return TokenNormalizer({"realise": "realize", "colour": "color"})
 | ||
| 
 | ||
| @German.factory("token_normalizer")
 | ||
| def create_de_normalizer(nlp, name):
 | ||
|     return TokenNormalizer({"daß": "dass", "wußte": "wusste"})
 | ||
| 
 | ||
| nlp_en = English()
 | ||
| nlp_en.add_pipe("token_normalizer")  # uses the English factory
 | ||
| print([token.norm_ for token in nlp_en("realise colour daß wußte")])
 | ||
| 
 | ||
| nlp_de = German()
 | ||
| nlp_de.add_pipe("token_normalizer")  # uses the German factory
 | ||
| print([token.norm_ for token in nlp_de("realise colour daß wußte")])
 | ||
| ```
 | ||
| 
 | ||
| <Infobox title="Implementation details">
 | ||
| 
 | ||
| Under the hood, language-specific factories are added to the
 | ||
| [`factories` registry](/api/top-level#registry) prefixed with the language code,
 | ||
| e.g. `"en.token_normalizer"`. When resolving the factory in
 | ||
| [`nlp.add_pipe`](/api/language#add_pipe), spaCy first checks for a
 | ||
| language-specific version of the factory using `nlp.lang` and if none is
 | ||
| available, falls back to looking up the regular factory name.
 | ||
| 
 | ||
| </Infobox>
 | ||
| 
 | ||
| ### Trainable components {#trainable-components new="3"}
 | ||
| 
 | ||
| spaCy's [`Pipe`](/api/pipe) class helps you implement your own trainable
 | ||
| components that have their own model instance, make predictions over `Doc`
 | ||
| objects and can be updated using [`spacy train`](/api/cli#train). This lets you
 | ||
| plug fully custom machine learning components into your pipeline. You'll need
 | ||
| the following:
 | ||
| 
 | ||
| 1. **Model:** A Thinc [`Model`](https://thinc.ai/docs/api-model) instance. This
 | ||
|    can be a model using [layers](https://thinc.ai/docs/api-layers) implemented
 | ||
|    in Thinc, or a [wrapped model](https://thinc.ai/docs/usage-frameworks)
 | ||
|    implemented in PyTorch, TensorFlow, MXNet or a fully custom solution. The
 | ||
|    model must take a list of [`Doc`](/api/doc) objects as input and can have any
 | ||
|    type of output.
 | ||
| 2. **Pipe subclass:** A subclass of [`Pipe`](/api/pipe) that implements at least
 | ||
|    two methods: [`Pipe.predict`](/api/pipe#predict) and
 | ||
|    [`Pipe.set_annotations`](/api/pipe#set_annotations).
 | ||
| 3. **Component factory:** A component factory registered with
 | ||
|    [`@Language.factory`](/api/language#factory) that takes the `nlp` object and
 | ||
|    component `name` and optional settings provided by the config and returns an
 | ||
|    instance of your trainable component.
 | ||
| 
 | ||
| > #### Example
 | ||
| >
 | ||
| > ```python
 | ||
| > from spacy.pipeline import Pipe
 | ||
| > from spacy.language import Language
 | ||
| >
 | ||
| > class TrainableComponent(Pipe):
 | ||
| >     def predict(self, docs):
 | ||
| >         ...
 | ||
| >
 | ||
| >     def set_annotations(self, docs, scores):
 | ||
| >         ...
 | ||
| >
 | ||
| > @Language.factory("my_trainable_component")
 | ||
| > def make_component(nlp, name, model):
 | ||
| >     return TrainableComponent(nlp.vocab, model, name=name)
 | ||
| > ```
 | ||
| 
 | ||
| | Name                                           | Description                                                                                                         |
 | ||
| | ---------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- |
 | ||
| | [`predict`](/api/pipe#predict)                 | Apply the component's model to a batch of [`Doc`](/api/doc) objects (without modifying them) and return the scores. |
 | ||
| | [`set_annotations`](/api/pipe#set_annotations) | Modify a batch of [`Doc`](/api/doc) objects, using pre-computed scores generated by `predict`.                      |
 | ||
| 
 | ||
| By default, [`Pipe.__init__`](/api/pipe#init) takes the shared vocab, the
 | ||
| [`Model`](https://thinc.ai/docs/api-model) and the name of the component
 | ||
| instance in the pipeline, which you can use as a key in the losses. All other
 | ||
| keyword arguments will become available as [`Pipe.cfg`](/api/pipe#cfg) and will
 | ||
| also be serialized with the component.
 | ||
| 
 | ||
| <Accordion title="Why components should be passed a Model instance, not create it" spaced>
 | ||
| 
 | ||
| spaCy's [config system](/usage/training#config) resolves the config describing
 | ||
| the pipeline components and models **bottom-up**. This means that it will
 | ||
| _first_ create a `Model` from a [registered architecture](/api/architectures),
 | ||
| validate its arguments and _then_ pass the object forward to the component. This
 | ||
| means that the config can express very complex, nested trees of objects – but
 | ||
| the objects don't have to pass the model settings all the way down to the
 | ||
| components. It also makes the components more **modular** and lets you swap
 | ||
| different architectures in your config, and re-use model definitions.
 | ||
| 
 | ||
| ```ini
 | ||
| ### config.cfg (excerpt)
 | ||
| [components]
 | ||
| 
 | ||
| [components.textcat]
 | ||
| factory = "textcat"
 | ||
| labels = []
 | ||
| 
 | ||
| # This function is created and then passed to the "textcat" component as
 | ||
| # the argument "model"
 | ||
| [components.textcat.model]
 | ||
| @architectures = "spacy.TextCatEnsemble.v1"
 | ||
| exclusive_classes = false
 | ||
| pretrained_vectors = null
 | ||
| width = 64
 | ||
| conv_depth = 2
 | ||
| embed_size = 2000
 | ||
| window_size = 1
 | ||
| ngram_size = 1
 | ||
| dropout = null
 | ||
| 
 | ||
| [components.other_textcat]
 | ||
| factory = "textcat"
 | ||
| # This references the [components.textcat.model] block above
 | ||
| model = ${components.textcat.model}
 | ||
| labels = []
 | ||
| ```
 | ||
| 
 | ||
| Your trainable pipeline component factories should therefore always take a
 | ||
| `model` argument instead of instantiating the
 | ||
| [`Model`](https://thinc.ai/docs/api-model) inside the component. To register
 | ||
| custom architectures, you can use the
 | ||
| [`@spacy.registry.architectures`](/api/top-level#registry) decorator. Also see
 | ||
| the [training guide](/usage/training#config) for details.
 | ||
| 
 | ||
| </Accordion>
 | ||
| 
 | ||
| For some use cases, it makes sense to also overwrite additional methods to
 | ||
| customize how the model is updated from examples, how it's initialized, how the
 | ||
| loss is calculated and to add evaluation scores to the training output.
 | ||
| 
 | ||
| | Name                                         | Description                                                                                                                                                                                                                                                                                                        |
 | ||
| | -------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
 | ||
| | [`update`](/api/pipe#update)                 | Learn from a batch of [`Example`](/api/example) objects containing the predictions and gold-standard annotations, and update the component's model.                                                                                                                                                                |
 | ||
| | [`begin_training`](/api/pipe#begin_training) | Initialize the model. Typically calls into [`Model.initialize`](https://thinc.ai/docs/api-model#initialize) and [`Pipe.create_optimizer`](/api/pipe#create_optimizer) if no optimizer is provided.                                                                                                                 |
 | ||
| | [`get_loss`](/api/pipe#get_loss)             | Return a tuple of the loss and the gradient for a batch of [`Example`](/api/example) objects.                                                                                                                                                                                                                      |
 | ||
| | [`score`](/api/pipe#score)                   | Score a batch of [`Example`](/api/example) objects and return a dictionary of scores. The [`@Language.factory`](/api/language#factory) decorator can define the `default_socre_weights` of the component to decide which keys of the scores to display during training and how they count towards the final score. |
 | ||
| 
 | ||
| <!-- TODO: add more details, examples and maybe an example project -->
 | ||
| 
 | ||
| ## Extension attributes {#custom-components-attributes new="2"}
 | ||
| 
 | ||
| spaCy allows you to set any custom attributes and methods on the `Doc`, `Span`
 | ||
| and `Token`, which become available as `Doc._`, `Span._` and `Token._` – for
 | ||
| example, `Token._.my_attr`. This lets you store additional information relevant
 | ||
| to your application, add new features and functionality to spaCy, and implement
 | ||
| your own models trained with other machine learning libraries. It also lets you
 | ||
| take advantage of spaCy's data structures and the `Doc` object as the "single
 | ||
| source of truth".
 | ||
| 
 | ||
| <Accordion title="Why ._ and not just a top-level attribute?" id="why-dot-underscore">
 | ||
| 
 | ||
| Writing to a `._` attribute instead of to the `Doc` directly keeps a clearer
 | ||
| separation and makes it easier to ensure backwards compatibility. For example,
 | ||
| if you've implemented your own `.coref` property and spaCy claims it one day,
 | ||
| it'll break your code. Similarly, just by looking at the code, you'll
 | ||
| immediately know what's built-in and what's custom – for example,
 | ||
| `doc.sentiment` is spaCy, while `doc._.sent_score` isn't.
 | ||
| 
 | ||
| </Accordion>
 | ||
| 
 | ||
| <Accordion title="How is the ._ implemented?" id="dot-underscore-implementation">
 | ||
| 
 | ||
| Extension definitions – the defaults, methods, getters and setters you pass in
 | ||
| to `set_extension` – are stored in class attributes on the `Underscore` class.
 | ||
| If you write to an extension attribute, e.g. `doc._.hello = True`, the data is
 | ||
| stored within the [`Doc.user_data`](/api/doc#attributes) dictionary. To keep the
 | ||
| underscore data separate from your other dictionary entries, the string `"._."`
 | ||
| is placed before the name, in a tuple.
 | ||
| 
 | ||
| </Accordion>
 | ||
| 
 | ||
| ---
 | ||
| 
 | ||
| There are three main types of extensions, which can be defined using the
 | ||
| [`Doc.set_extension`](/api/doc#set_extension),
 | ||
| [`Span.set_extension`](/api/span#set_extension) and
 | ||
| [`Token.set_extension`](/api/token#set_extension) methods.
 | ||
| 
 | ||
| 1. **Attribute extensions.** Set a default value for an attribute, which can be
 | ||
|    overwritten manually at any time. Attribute extensions work like "normal"
 | ||
|    variables and are the quickest way to store arbitrary information on a `Doc`,
 | ||
|    `Span` or `Token`.
 | ||
| 
 | ||
|    ```python
 | ||
|     Doc.set_extension("hello", default=True)
 | ||
|     assert doc._.hello
 | ||
|     doc._.hello = False
 | ||
|    ```
 | ||
| 
 | ||
| 2. **Property extensions.** Define a getter and an optional setter function. If
 | ||
|    no setter is provided, the extension is immutable. Since the getter and
 | ||
|    setter functions are only called when you _retrieve_ the attribute, you can
 | ||
|    also access values of previously added attribute extensions. For example, a
 | ||
|    `Doc` getter can average over `Token` attributes. For `Span` extensions,
 | ||
|    you'll almost always want to use a property – otherwise, you'd have to write
 | ||
|    to _every possible_ `Span` in the `Doc` to set up the values correctly.
 | ||
| 
 | ||
|    ```python
 | ||
|    Doc.set_extension("hello", getter=get_hello_value, setter=set_hello_value)
 | ||
|    assert doc._.hello
 | ||
|    doc._.hello = "Hi!"
 | ||
|    ```
 | ||
| 
 | ||
| 3. **Method extensions.** Assign a function that becomes available as an object
 | ||
|    method. Method extensions are always immutable. For more details and
 | ||
|    implementation ideas, see
 | ||
|    [these examples](/usage/examples#custom-components-attr-methods).
 | ||
| 
 | ||
|    ```python
 | ||
|    Doc.set_extension("hello", method=lambda doc, name: f"Hi {name}!")
 | ||
|    assert doc._.hello("Bob") == "Hi Bob!"
 | ||
|    ```
 | ||
| 
 | ||
| Before you can access a custom extension, you need to register it using the
 | ||
| `set_extension` method on the object you want to add it to, e.g. the `Doc`. Keep
 | ||
| in mind that extensions are always **added globally** and not just on a
 | ||
| particular instance. If an attribute of the same name already exists, or if
 | ||
| you're trying to access an attribute that hasn't been registered, spaCy will
 | ||
| raise an `AttributeError`.
 | ||
| 
 | ||
| ```python
 | ||
| ### Example
 | ||
| from spacy.tokens import Doc, Span, Token
 | ||
| 
 | ||
| fruits = ["apple", "pear", "banana", "orange", "strawberry"]
 | ||
| is_fruit_getter = lambda token: token.text in fruits
 | ||
| has_fruit_getter = lambda obj: any([t.text in fruits for t in obj])
 | ||
| 
 | ||
| Token.set_extension("is_fruit", getter=is_fruit_getter)
 | ||
| Doc.set_extension("has_fruit", getter=has_fruit_getter)
 | ||
| Span.set_extension("has_fruit", getter=has_fruit_getter)
 | ||
| ```
 | ||
| 
 | ||
| > #### Usage example
 | ||
| >
 | ||
| > ```python
 | ||
| > doc = nlp("I have an apple and a melon")
 | ||
| > assert doc[3]._.is_fruit      # get Token attributes
 | ||
| > assert not doc[0]._.is_fruit
 | ||
| > assert doc._.has_fruit        # get Doc attributes
 | ||
| > assert doc[1:4]._.has_fruit   # get Span attributes
 | ||
| > ```
 | ||
| 
 | ||
| Once you've registered your custom attribute, you can also use the built-in
 | ||
| `set`, `get` and `has` methods to modify and retrieve the attributes. This is
 | ||
| especially useful it you want to pass in a string instead of calling
 | ||
| `doc._.my_attr`.
 | ||
| 
 | ||
| ### Example: Pipeline component for GPE entities and country meta data via a REST API {#component-example3}
 | ||
| 
 | ||
| This example shows the implementation of a pipeline component that fetches
 | ||
| country meta data via the [REST Countries API](https://restcountries.eu), sets
 | ||
| entity annotations for countries, merges entities into one token and sets custom
 | ||
| attributes on the `Doc`, `Span` and `Token` – for example, the capital,
 | ||
| latitude/longitude coordinates and even the country flag.
 | ||
| 
 | ||
| ```python
 | ||
| ### {executable="true"}
 | ||
| import requests
 | ||
| from spacy.lang.en import English
 | ||
| from spacy.language import Language
 | ||
| from spacy.matcher import PhraseMatcher
 | ||
| from spacy.tokens import Doc, Span, Token
 | ||
| 
 | ||
| @Language.factory("rest_countries")
 | ||
| class RESTCountriesComponent:
 | ||
|     def __init__(self, nlp, name, label="GPE"):
 | ||
|         r = requests.get("https://restcountries.eu/rest/v2/all")
 | ||
|         r.raise_for_status()  # make sure requests raises an error if it fails
 | ||
|         countries = r.json()
 | ||
|         # Convert API response to dict keyed by country name for easy lookup
 | ||
|         self.countries = {c["name"]: c for c in countries}
 | ||
|         self.label = label
 | ||
|         # Set up the PhraseMatcher with Doc patterns for each country name
 | ||
|         self.matcher = PhraseMatcher(nlp.vocab)
 | ||
|         self.matcher.add("COUNTRIES", [nlp.make_doc(c) for c in self.countries.keys()])
 | ||
|         # Register attribute on the Token. We'll be overwriting this based on
 | ||
|         # the matches, so we're only setting a default value, not a getter.
 | ||
|         Token.set_extension("is_country", default=False)
 | ||
|         Token.set_extension("country_capital", default=False)
 | ||
|         Token.set_extension("country_latlng", default=False)
 | ||
|         Token.set_extension("country_flag", default=False)
 | ||
|         # Register attributes on Doc and Span via a getter that checks if one of
 | ||
|         # the contained tokens is set to is_country == True.
 | ||
|         Doc.set_extension("has_country", getter=self.has_country)
 | ||
|         Span.set_extension("has_country", getter=self.has_country)
 | ||
| 
 | ||
|     def __call__(self, doc):
 | ||
|         spans = []  # keep the spans for later so we can merge them afterwards
 | ||
|         for _, start, end in self.matcher(doc):
 | ||
|             # Generate Span representing the entity & set label
 | ||
|             entity = Span(doc, start, end, label=self.label)
 | ||
|             spans.append(entity)
 | ||
|             # Set custom attribute on each token of the entity
 | ||
|             # Can be extended with other data returned by the API, like
 | ||
|             # currencies, country code, flag, calling code etc.
 | ||
|             for token in entity:
 | ||
|                 token._.set("is_country", True)
 | ||
|                 token._.set("country_capital", self.countries[entity.text]["capital"])
 | ||
|                 token._.set("country_latlng", self.countries[entity.text]["latlng"])
 | ||
|                 token._.set("country_flag", self.countries[entity.text]["flag"])
 | ||
|         # Iterate over all spans and merge them into one token
 | ||
|         with doc.retokenize() as retokenizer:
 | ||
|             for span in spans:
 | ||
|                 retokenizer.merge(span)
 | ||
|         # Overwrite doc.ents and add entity – be careful not to replace!
 | ||
|         doc.ents = list(doc.ents) + spans
 | ||
|         return doc  # don't forget to return the Doc!
 | ||
| 
 | ||
|     def has_country(self, tokens):
 | ||
|         """Getter for Doc and Span attributes. Since the getter is only called
 | ||
|         when we access the attribute, we can refer to the Token's 'is_country'
 | ||
|         attribute here, which is already set in the processing step."""
 | ||
|         return any([t._.get("is_country") for t in tokens])
 | ||
| 
 | ||
| nlp = English()
 | ||
| nlp.add_pipe("rest_countries", config={"label": "GPE"})
 | ||
| doc = nlp("Some text about Colombia and the Czech Republic")
 | ||
| print("Pipeline", nlp.pipe_names)  # pipeline contains component name
 | ||
| print("Doc has countries", doc._.has_country)  # Doc contains countries
 | ||
| for token in doc:
 | ||
|     if token._.is_country:
 | ||
|         print(token.text, token._.country_capital, token._.country_latlng, token._.country_flag)
 | ||
| print("Entities", [(e.text, e.label_) for e in doc.ents])
 | ||
| ```
 | ||
| 
 | ||
| In this case, all data can be fetched on initialization in one request. However,
 | ||
| if you're working with text that contains incomplete country names, spelling
 | ||
| mistakes or foreign-language versions, you could also implement a
 | ||
| `like_country`-style getter function that makes a request to the search API
 | ||
| endpoint and returns the best-matching result.
 | ||
| 
 | ||
| ### User hooks {#custom-components-user-hooks}
 | ||
| 
 | ||
| While it's generally recommended to use the `Doc._`, `Span._` and `Token._`
 | ||
| proxies to add your own custom attributes, spaCy offers a few exceptions to
 | ||
| allow **customizing the built-in methods** like
 | ||
| [`Doc.similarity`](/api/doc#similarity) or [`Doc.vector`](/api/doc#vector) with
 | ||
| your own hooks, which can rely on statistical models you train yourself. For
 | ||
| instance, you can provide your own on-the-fly sentence segmentation algorithm or
 | ||
| document similarity method.
 | ||
| 
 | ||
| Hooks let you customize some of the behaviors of the `Doc`, `Span` or `Token`
 | ||
| objects by adding a component to the pipeline. For instance, to customize the
 | ||
| [`Doc.similarity`](/api/doc#similarity) method, you can add a component that
 | ||
| sets a custom function to `doc.user_hooks['similarity']`. The built-in
 | ||
| `Doc.similarity` method will check the `user_hooks` dict, and delegate to your
 | ||
| function if you've set one. Similar results can be achieved by setting functions
 | ||
| to `Doc.user_span_hooks` and `Doc.user_token_hooks`.
 | ||
| 
 | ||
| > #### Implementation note
 | ||
| >
 | ||
| > The hooks live on the `Doc` object because the `Span` and `Token` objects are
 | ||
| > created lazily, and don't own any data. They just proxy to their parent `Doc`.
 | ||
| > This turns out to be convenient here — we only have to worry about installing
 | ||
| > hooks in one place.
 | ||
| 
 | ||
| | Name               | Customizes                                                                                                                                                                                                              |
 | ||
| | ------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | ||
| | `user_hooks`       | [`Doc.vector`](/api/doc#vector), [`Doc.has_vector`](/api/doc#has_vector), [`Doc.vector_norm`](/api/doc#vector_norm), [`Doc.sents`](/api/doc#sents)                                                                      |
 | ||
| | `user_token_hooks` | [`Token.similarity`](/api/token#similarity), [`Token.vector`](/api/token#vector), [`Token.has_vector`](/api/token#has_vector), [`Token.vector_norm`](/api/token#vector_norm), [`Token.conjuncts`](/api/token#conjuncts) |
 | ||
| | `user_span_hooks`  | [`Span.similarity`](/api/span#similarity), [`Span.vector`](/api/span#vector), [`Span.has_vector`](/api/span#has_vector), [`Span.vector_norm`](/api/span#vector_norm), [`Span.root`](/api/span#root)                     |
 | ||
| 
 | ||
| ```python
 | ||
| ### Add custom similarity hooks
 | ||
| class SimilarityModel:
 | ||
|     def __init__(self, model):
 | ||
|         self._model = model
 | ||
| 
 | ||
|     def __call__(self, doc):
 | ||
|         doc.user_hooks["similarity"] = self.similarity
 | ||
|         doc.user_span_hooks["similarity"] = self.similarity
 | ||
|         doc.user_token_hooks["similarity"] = self.similarity
 | ||
| 
 | ||
|     def similarity(self, obj1, obj2):
 | ||
|         y = self._model([obj1.vector, obj2.vector])
 | ||
|         return float(y[0])
 | ||
| ```
 | ||
| 
 | ||
| ## Developing plugins and wrappers {#plugins}
 | ||
| 
 | ||
| We're very excited about all the new possibilities for community extensions and
 | ||
| plugins in spaCy, and we can't wait to see what you build with it! To get you
 | ||
| started, here are a few tips, tricks and best
 | ||
| practices. [See here](/universe/?category=pipeline) for examples of other spaCy
 | ||
| extensions.
 | ||
| 
 | ||
| ### Usage ideas {#custom-components-usage-ideas}
 | ||
| 
 | ||
| - **Adding new features and hooking in models.** For example, a sentiment
 | ||
|   analysis model, or your preferred solution for lemmatization or sentiment
 | ||
|   analysis. spaCy's built-in tagger, parser and entity recognizer respect
 | ||
|   annotations that were already set on the `Doc` in a previous step of the
 | ||
|   pipeline.
 | ||
| - **Integrating other libraries and APIs.** For example, your pipeline component
 | ||
|   can write additional information and data directly to the `Doc` or `Token` as
 | ||
|   custom attributes, while making sure no information is lost in the process.
 | ||
|   This can be output generated by other libraries and models, or an external
 | ||
|   service with a REST API.
 | ||
| - **Debugging and logging.** For example, a component which stores and/or
 | ||
|   exports relevant information about the current state of the processed
 | ||
|   document, and insert it at any point of your pipeline.
 | ||
| 
 | ||
| ### Best practices {#custom-components-best-practices}
 | ||
| 
 | ||
| Extensions can claim their own `._` namespace and exist as standalone packages.
 | ||
| If you're developing a tool or library and want to make it easy for others to
 | ||
| use it with spaCy and add it to their pipeline, all you have to do is expose a
 | ||
| function that takes a `Doc`, modifies it and returns it.
 | ||
| 
 | ||
| - Make sure to choose a **descriptive and specific name** for your pipeline
 | ||
|   component class, and set it as its `name` attribute. Avoid names that are too
 | ||
|   common or likely to clash with built-in or a user's other custom components.
 | ||
|   While it's fine to call your package `"spacy_my_extension"`, avoid component
 | ||
|   names including `"spacy"`, since this can easily lead to confusion.
 | ||
| 
 | ||
|   ```diff
 | ||
|   + name = "myapp_lemmatizer"
 | ||
|   - name = "lemmatizer"
 | ||
|   ```
 | ||
| 
 | ||
| - When writing to `Doc`, `Token` or `Span` objects, **use getter functions**
 | ||
|   wherever possible, and avoid setting values explicitly. Tokens and spans don't
 | ||
|   own any data themselves, and they're implemented as C extension classes – so
 | ||
|   you can't usually add new attributes to them like you could with most pure
 | ||
|   Python objects.
 | ||
| 
 | ||
|   ```diff
 | ||
|   + is_fruit = lambda token: token.text in ("apple", "orange")
 | ||
|   + Token.set_extension("is_fruit", getter=is_fruit)
 | ||
| 
 | ||
|   - token._.set_extension("is_fruit", default=False)
 | ||
|   - if token.text in ('"apple", "orange"):
 | ||
|   -     token._.set("is_fruit", True)
 | ||
|   ```
 | ||
| 
 | ||
| - Always add your custom attributes to the **global** `Doc`, `Token` or `Span`
 | ||
|   objects, not a particular instance of them. Add the attributes **as early as
 | ||
|   possible**, e.g. in your extension's `__init__` method or in the global scope
 | ||
|   of your module. This means that in the case of namespace collisions, the user
 | ||
|   will see an error immediately, not just when they run their pipeline.
 | ||
| 
 | ||
|   ```diff
 | ||
|   + from spacy.tokens import Doc
 | ||
|   + def __init__(attr="my_attr"):
 | ||
|   +     Doc.set_extension(attr, getter=self.get_doc_attr)
 | ||
| 
 | ||
|   - def __call__(doc):
 | ||
|   -     doc.set_extension("my_attr", getter=self.get_doc_attr)
 | ||
|   ```
 | ||
| 
 | ||
| - If your extension is setting properties on the `Doc`, `Token` or `Span`,
 | ||
|   include an option to **let the user to change those attribute names**. This
 | ||
|   makes it easier to avoid namespace collisions and accommodate users with
 | ||
|   different naming preferences. We recommend adding an `attrs` argument to the
 | ||
|   `__init__` method of your class so you can write the names to class attributes
 | ||
|   and reuse them across your component.
 | ||
| 
 | ||
|   ```diff
 | ||
|   + Doc.set_extension(self.doc_attr, default="some value")
 | ||
|   - Doc.set_extension("my_doc_attr", default="some value")
 | ||
|   ```
 | ||
| 
 | ||
| - Ideally, extensions should be **standalone packages** with spaCy and
 | ||
|   optionally, other packages specified as a dependency. They can freely assign
 | ||
|   to their own `._` namespace, but should stick to that. If your extension's
 | ||
|   only job is to provide a better `.similarity` implementation, and your docs
 | ||
|   state this explicitly, there's no problem with writing to the
 | ||
|   [`user_hooks`](#custom-components-user-hooks) and overwriting spaCy's built-in
 | ||
|   method. However, a third-party extension should **never silently overwrite
 | ||
|   built-ins**, or attributes set by other extensions.
 | ||
| 
 | ||
| - If you're looking to publish a model that depends on a custom pipeline
 | ||
|   component, you can either **require it** in the model package's dependencies,
 | ||
|   or – if the component is specific and lightweight – choose to **ship it with
 | ||
|   your model package** and add it to the `Language` instance returned by the
 | ||
|   model's `load()` method. For examples of this, check out the implementations
 | ||
|   of spaCy's
 | ||
|   [`load_model_from_init_py`](/api/top-level#util.load_model_from_init_py)
 | ||
|   [`load_model_from_path`](/api/top-level#util.load_model_from_path) utility
 | ||
|   functions.
 | ||
| 
 | ||
| - Once you're ready to share your extension with others, make sure to **add docs
 | ||
|   and installation instructions** (you can always link to this page for more
 | ||
|   info). Make it easy for others to install and use your extension, for example
 | ||
|   by uploading it to [PyPi](https://pypi.python.org). If you're sharing your
 | ||
|   code on GitHub, don't forget to tag it with
 | ||
|   [`spacy`](https://github.com/topics/spacy?o=desc&s=stars) and
 | ||
|   [`spacy-extension`](https://github.com/topics/spacy-extension?o=desc&s=stars)
 | ||
|   to help people find it. If you post it on Twitter, feel free to tag
 | ||
|   [@spacy_io](https://twitter.com/spacy_io) so we can check it out.
 | ||
| 
 | ||
| ### Wrapping other models and libraries {#wrapping-models-libraries}
 | ||
| 
 | ||
| Let's say you have a custom entity recognizer that takes a list of strings and
 | ||
| returns their [BILUO tags](/usage/linguistic-features#accessing-ner). Given an
 | ||
| input like `["A", "text", "about", "Facebook"]`, it will predict and return
 | ||
| `["O", "O", "O", "U-ORG"]`. To integrate it into your spaCy pipeline and make it
 | ||
| add those entities to the `doc.ents`, you can wrap it in a custom pipeline
 | ||
| component function and pass it the token texts from the `Doc` object received by
 | ||
| the component.
 | ||
| 
 | ||
| The [`gold.spans_from_biluo_tags`](/api/top-level#spans_from_biluo_tags) is very
 | ||
| helpful here, because it takes a `Doc` object and token-based BILUO tags and
 | ||
| returns a sequence of `Span` objects in the `Doc` with added labels. So all your
 | ||
| wrapper has to do is compute the entity spans and overwrite the `doc.ents`.
 | ||
| 
 | ||
| > #### How the doc.ents work
 | ||
| >
 | ||
| > When you add spans to the `doc.ents`, spaCy will automatically resolve them
 | ||
| > back to the underlying tokens and set the `Token.ent_type` and `Token.ent_iob`
 | ||
| > attributes. By definition, each token can only be part of one entity, so
 | ||
| > overlapping entity spans are not allowed.
 | ||
| 
 | ||
| ```python
 | ||
| ### {highlight="1,8-9"}
 | ||
| import your_custom_entity_recognizer
 | ||
| from spacy.gold import offsets_from_biluo_tags
 | ||
| from spacy.language import Language
 | ||
| 
 | ||
| @Language.component("custom_ner_wrapper")
 | ||
| def custom_ner_wrapper(doc):
 | ||
|     words = [token.text for token in doc]
 | ||
|     custom_entities = your_custom_entity_recognizer(words)
 | ||
|     doc.ents = spans_from_biluo_tags(doc, custom_entities)
 | ||
|     return doc
 | ||
| ```
 | ||
| 
 | ||
| The `custom_ner_wrapper` can then be added to the pipeline of a blank model
 | ||
| using [`nlp.add_pipe`](/api/language#add_pipe). You can also replace the
 | ||
| existing entity recognizer of a pretrained model with
 | ||
| [`nlp.replace_pipe`](/api/language#replace_pipe).
 | ||
| 
 | ||
| Here's another example of a custom model, `your_custom_model`, that takes a list
 | ||
| of tokens and returns lists of fine-grained part-of-speech tags, coarse-grained
 | ||
| part-of-speech tags, dependency labels and head token indices. Here, we can use
 | ||
| the [`Doc.from_array`](/api/doc#from_array) to create a new `Doc` object using
 | ||
| those values. To create a numpy array we need integers, so we can look up the
 | ||
| string labels in the [`StringStore`](/api/stringstore). The
 | ||
| [`doc.vocab.strings.add`](/api/stringstore#add) method comes in handy here,
 | ||
| because it returns the integer ID of the string _and_ makes sure it's added to
 | ||
| the vocab. This is especially important if the custom model uses a different
 | ||
| label scheme than spaCy's default models.
 | ||
| 
 | ||
| > #### Example: spacy-stanza
 | ||
| >
 | ||
| > For an example of an end-to-end wrapper for statistical tokenization, tagging
 | ||
| > and parsing, check out
 | ||
| > [`spacy-stanza`](https://github.com/explosion/spacy-stanza). It uses a very
 | ||
| > similar approach to the example in this section – the only difference is that
 | ||
| > it fully replaces the `nlp` object instead of providing a pipeline component,
 | ||
| > since it also needs to handle tokenization.
 | ||
| 
 | ||
| ```python
 | ||
| ### {highlight="1,11,17-19"}
 | ||
| import your_custom_model
 | ||
| from spacy.language import Language
 | ||
| from spacy.symbols import POS, TAG, DEP, HEAD
 | ||
| from spacy.tokens import Doc
 | ||
| import numpy
 | ||
| 
 | ||
| @Language.component("custom_model_wrapper")
 | ||
| def custom_model_wrapper(doc):
 | ||
|     words = [token.text for token in doc]
 | ||
|     spaces = [token.whitespace for token in doc]
 | ||
|     pos, tags, deps, heads = your_custom_model(words)
 | ||
|     # Convert the strings to integers and add them to the string store
 | ||
|     pos = [doc.vocab.strings.add(label) for label in pos]
 | ||
|     tags = [doc.vocab.strings.add(label) for label in tags]
 | ||
|     deps = [doc.vocab.strings.add(label) for label in deps]
 | ||
|     # Create a new Doc from a numpy array
 | ||
|     attrs = [POS, TAG, DEP, HEAD]
 | ||
|     arr = numpy.array(list(zip(pos, tags, deps, heads)), dtype="uint64")
 | ||
|     new_doc = Doc(doc.vocab, words=words, spaces=spaces).from_array(attrs, arr)
 | ||
|     return new_doc
 | ||
| ```
 | ||
| 
 | ||
| <Infobox title="Sentence boundaries and heads" variant="warning">
 | ||
| 
 | ||
| If you create a `Doc` object with dependencies and heads, spaCy is able to
 | ||
| resolve the sentence boundaries automatically. However, note that the `HEAD`
 | ||
| value used to construct a `Doc` is the token index **relative** to the current
 | ||
| token – e.g. `-1` for the previous token. The CoNLL format typically annotates
 | ||
| heads as `1`-indexed absolute indices with `0` indicating the root. If that's
 | ||
| the case in your annotations, you need to convert them first:
 | ||
| 
 | ||
| ```python
 | ||
| heads = [2, 0, 4, 2, 2]
 | ||
| new_heads = [head - i - 1 if head != 0 else 0 for i, head in enumerate(heads)]
 | ||
| ```
 | ||
| 
 | ||
| </Infobox>
 | ||
| 
 | ||
| <Infobox title="Advanced usage, serialization and entry points" emoji="📖">
 | ||
| 
 | ||
| For more details on how to write and package custom components, make them
 | ||
| available to spaCy via entry points and implement your own serialization
 | ||
| methods, check out the usage guide on
 | ||
| [saving and loading](/usage/saving-loading).
 | ||
| 
 | ||
| </Infobox>
 |