spaCy/website/docs/api/lookups.md
2020-05-24 17:23:00 +02:00

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---
title: Lookups
teaser: A container for large lookup tables and dictionaries
tag: class
source: spacy/lookups.py
new: 2.2
---
This class allows convenient access to large lookup tables and dictionaries,
e.g. lemmatization data or tokenizer exception lists using Bloom filters.
Lookups are available via the [`Vocab`](/api/vocab) as `vocab.lookups`, so they
can be accessed before the pipeline components are applied (e.g. in the
tokenizer and lemmatizer), as well as within the pipeline components via
`doc.vocab.lookups`.
## Lookups.\_\_init\_\_ {#init tag="method"}
Create a `Lookups` object.
> #### Example
>
> ```python
> from spacy.lookups import Lookups
> lookups = Lookups()
> ```
| Name | Type | Description |
| ----------- | --------- | ----------------------------- |
| **RETURNS** | `Lookups` | The newly constructed object. |
## Lookups.\_\_len\_\_ {#len tag="method"}
Get the current number of tables in the lookups.
> #### Example
>
> ```python
> lookups = Lookups()
> assert len(lookups) == 0
> ```
| Name | Type | Description |
| ----------- | ---- | ------------------------------------ |
| **RETURNS** | int | The number of tables in the lookups. |
## Lookups.\_\contains\_\_ {#contains tag="method"}
Check if the lookups contain a table of a given name. Delegates to
[`Lookups.has_table`](/api/lookups#has_table).
> #### Example
>
> ```python
> lookups = Lookups()
> lookups.add_table("some_table")
> assert "some_table" in lookups
> ```
| Name | Type | Description |
| ----------- | ---- | ----------------------------------------------- |
| `name` | str | Name of the table. |
| **RETURNS** | bool | Whether a table of that name is in the lookups. |
## Lookups.tables {#tables tag="property"}
Get the names of all tables in the lookups.
> #### Example
>
> ```python
> lookups = Lookups()
> lookups.add_table("some_table")
> assert lookups.tables == ["some_table"]
> ```
| Name | Type | Description |
| ----------- | ---- | ----------------------------------- |
| **RETURNS** | list | Names of the tables in the lookups. |
## Lookups.add_table {#add_table tag="method"}
Add a new table with optional data to the lookups. Raises an error if the table
exists.
> #### Example
>
> ```python
> lookups = Lookups()
> lookups.add_table("some_table", {"foo": "bar"})
> ```
| Name | Type | Description |
| ----------- | ----------------------------- | ---------------------------------- |
| `name` | str | Unique name of the table. |
| `data` | dict | Optional data to add to the table. |
| **RETURNS** | [`Table`](/api/lookups#table) | The newly added table. |
## Lookups.get_table {#get_table tag="method"}
Get a table from the lookups. Raises an error if the table doesn't exist.
> #### Example
>
> ```python
> lookups = Lookups()
> lookups.add_table("some_table", {"foo": "bar"})
> table = lookups.get_table("some_table")
> assert table["foo"] == "bar"
> ```
| Name | Type | Description |
| ----------- | ----------------------------- | ------------------ |
| `name` | str | Name of the table. |
| **RETURNS** | [`Table`](/api/lookups#table) | The table. |
## Lookups.remove_table {#remove_table tag="method"}
Remove a table from the lookups. Raises an error if the table doesn't exist.
> #### Example
>
> ```python
> lookups = Lookups()
> lookups.add_table("some_table")
> removed_table = lookups.remove_table("some_table")
> assert "some_table" not in lookups
> ```
| Name | Type | Description |
| ----------- | ----------------------------- | ---------------------------- |
| `name` | str | Name of the table to remove. |
| **RETURNS** | [`Table`](/api/lookups#table) | The removed table. |
## Lookups.has_table {#has_table tag="method"}
Check if the lookups contain a table of a given name. Equivalent to
[`Lookups.__contains__`](/api/lookups#contains).
> #### Example
>
> ```python
> lookups = Lookups()
> lookups.add_table("some_table")
> assert lookups.has_table("some_table")
> ```
| Name | Type | Description |
| ----------- | ---- | ----------------------------------------------- |
| `name` | str | Name of the table. |
| **RETURNS** | bool | Whether a table of that name is in the lookups. |
## Lookups.to_bytes {#to_bytes tag="method"}
Serialize the lookups to a bytestring.
> #### Example
>
> ```python
> lookup_bytes = lookups.to_bytes()
> ```
| Name | Type | Description |
| ----------- | ----- | ----------------------- |
| **RETURNS** | bytes | The serialized lookups. |
## Lookups.from_bytes {#from_bytes tag="method"}
Load the lookups from a bytestring.
> #### Example
>
> ```python
> lookup_bytes = lookups.to_bytes()
> lookups = Lookups()
> lookups.from_bytes(lookup_bytes)
> ```
| Name | Type | Description |
| ------------ | --------- | ---------------------- |
| `bytes_data` | bytes | The data to load from. |
| **RETURNS** | `Lookups` | The loaded lookups. |
## Lookups.to_disk {#to_disk tag="method"}
Save the lookups to a directory as `lookups.bin`. Expects a path to a directory,
which will be created if it doesn't exist.
> #### Example
>
> ```python
> lookups.to_disk("/path/to/lookups")
> ```
| Name | Type | Description |
| ------ | ------------ | --------------------------------------------------------------------------------------------------------------------- |
| `path` | str / `Path` | A path to a directory, which will be created if it doesn't exist. Paths may be either strings or `Path`-like objects. |
## Lookups.from_disk {#from_disk tag="method"}
Load lookups from a directory containing a `lookups.bin`. Will skip loading if
the file doesn't exist.
> #### Example
>
> ```python
> from spacy.lookups import Lookups
> lookups = Lookups()
> lookups.from_disk("/path/to/lookups")
> ```
| Name | Type | Description |
| ----------- | ------------ | -------------------------------------------------------------------------- |
| `path` | str / `Path` | A path to a directory. Paths may be either strings or `Path`-like objects. |
| **RETURNS** | `Lookups` | The loaded lookups. |
## Table {#table tag="class, ordererddict"}
A table in the lookups. Subclass of `OrderedDict` that implements a slightly
more consistent and unified API and includes a Bloom filter to speed up missed
lookups. Supports **all other methods and attributes** of `OrderedDict` /
`dict`, and the customized methods listed here. Methods that get or set keys
accept both integers and strings (which will be hashed before being added to the
table).
### Table.\_\_init\_\_ {#table.init tag="method"}
Initialize a new table.
> #### Example
>
> ```python
> from spacy.lookups import Table
> data = {"foo": "bar", "baz": 100}
> table = Table(name="some_table", data=data)
> assert "foo" in table
> assert table["foo"] == "bar"
> ```
| Name | Type | Description |
| ----------- | ------- | ---------------------------------- |
| `name` | str | Optional table name for reference. |
| **RETURNS** | `Table` | The newly constructed object. |
### Table.from_dict {#table.from_dict tag="classmethod"}
Initialize a new table from a dict.
> #### Example
>
> ```python
> from spacy.lookups import Table
> data = {"foo": "bar", "baz": 100}
> table = Table.from_dict(data, name="some_table")
> ```
| Name | Type | Description |
| ----------- | ------- | ---------------------------------- |
| `data` | dict | The dictionary. |
| `name` | str | Optional table name for reference. |
| **RETURNS** | `Table` | The newly constructed object. |
### Table.set {#table.set tag="method"}
Set a new key / value pair. String keys will be hashed. Same as
`table[key] = value`.
> #### Example
>
> ```python
> from spacy.lookups import Table
> table = Table()
> table.set("foo", "bar")
> assert table["foo"] == "bar"
> ```
| Name | Type | Description |
| ------- | --------- | ----------- |
| `key` | str / int | The key. |
| `value` | - | The value. |
### Table.to_bytes {#table.to_bytes tag="method"}
Serialize the table to a bytestring.
> #### Example
>
> ```python
> table_bytes = table.to_bytes()
> ```
| Name | Type | Description |
| ----------- | ----- | --------------------- |
| **RETURNS** | bytes | The serialized table. |
### Table.from_bytes {#table.from_bytes tag="method"}
Load a table from a bytestring.
> #### Example
>
> ```python
> table_bytes = table.to_bytes()
> table = Table()
> table.from_bytes(table_bytes)
> ```
| Name | Type | Description |
| ------------ | ------- | ----------------- |
| `bytes_data` | bytes | The data to load. |
| **RETURNS** | `Table` | The loaded table. |
### Attributes {#table-attributes}
| Name | Type | Description |
| -------------- | --------------------------- | ----------------------------------------------------- |
| `name` | str | Table name. |
| `default_size` | int | Default size of bloom filters if no data is provided. |
| `bloom` | `preshed.bloom.BloomFilter` | The bloom filters. |