llm/docs/embeddings/python-api.md

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(embeddings-python-api)=
# Using embeddings from Python
You can load an embedding model using its model ID or alias like this:
```python
import llm
embedding_model = llm.get_embedding_model("ada-002")
```
To embed a string, returning a Python list of floating point numbers, use the `.embed()` method:
```python
vector = embedding_model.embed("my happy hound")
```
Many embeddings models are more efficient when you embed multiple strings at once. To embed multiple strings at once, use the `.embed_multi()` method:
```python
vectors = list(embedding_model.embed_multi(["my happy hound", "my dissatisfied cat"]))
```
This returns a generator that yields one embedding vector per string.
(embeddings-python-collections)=
## Working with collections
The `llm.Collection` class can be used to work with **collections** of embeddings from Python code.
A collection is a named group of embedding vectors, each stored along with their IDs in a SQLite database table.
To work with embeddings in this way you will need an instance of a [sqlite-utils Database](https://sqlite-utils.datasette.io/en/stable/python-api.html#connecting-to-or-creating-a-database) object. You can then pass that to the `llm.Collection` constructor along with the unique string name of the collection and the ID of the embedding model you will be using with that collection:
```python
import sqlite_utils
import llm
db = sqlite_utils.Database("my-embeddings.db")
# Pass model_id= to specify a model for the collection
collection = llm.Collection(db, "entries", model_id="ada-002")
# Or you can pass a model directly using model=
embedding_model = llm.get_embedding_model("ada-002")
collection = llm.Collection(db, "entries", model=embedding_model)
```
If the collection already exists in the database you can omit the `model` or `model_id` argument - the model ID will be read from the `collections` table.
To embed a single string and store it in the collection, use the `embed()` method:
```python
collection.embed("hound", "my happy hound")
```
This stores the embedding for the string "my happy hound" in the `entries` collection under the key `hound`.
Add `store=True` to store the text content itself in the database table along with the embedding vector.
To attach additional metadata to an item, pass a JSON-compatible dictionary as the `metadata=` argument:
```python
collection.embed("hound", "my happy hound", metadata={"name": "Hound"}, store=True)
```
This additional metadata will be stored as JSON in the `metadata` column of the embeddings database table.
(embeddings-python-bulk)=
### Storing embeddings in bulk
The `collection.embed_multi()` method can be used to store embeddings for multiple strings at once. This can be more efficient for some embedding models.
```python
collection.embed_multi(
[
("hound", "my happy hound"),
("cat", "my dissatisfied cat"),
],
# Add this to store the strings in the content column:
store=True,
)
```
To include metadata to be stored with each item, call `embed_multi_with_metadata()`:
```python
collection.embed_multi_with_metadata(
[
("hound", "my happy hound", {"name": "Hound"}),
("cat", "my dissatisfied cat", {"name": "Cat"}),
],
# This can also take the store=True argument:
store=True,
)
```
(embeddings-python-similar)=
## Retrieving similar items
Once you have populated a collection of embeddings you can retrieve the entries that are most similar to a given string using the `similar()` method:
```python
for entry in collection.similar("hound"):
print(entry.id, entry.score)
```
The string will first by embedded using the model for the collection.
The `entry` object returned is an object with the following properties:
- `id` - the string ID of the item
- `score` - the floating point similarity score between the item and the query string
- `content` - the string text content of the item, if it was stored - or `None`
- `metadata` - the dictionary (from JSON) metadata for the item, if it was stored - or `None`
This defaults to returning the 10 most similar items. You can change this by passing a different `number=` argument:
```python
for id, score in collection.similar("hound", number=5):
print(id, score)
```
The `similar_by_id()` method takes the ID of another item in the collection and returns the most similar items to that one, based on the embedding that has already been stored for it:
```python
for id, score in collection.similar_by_id("cat"):
print(id, score)
```
The item itself is excluded from the results.