wip: make the python API reference a bit nicer (#162)

Adds:

* Make `mkdocstrings` aware we are using numpy-style docstrings
* Fixes broken link on `index.md` to Python API docs (and added link to
node ones)
* Added examples to various classes.
* Added doctest to verify examples work.
This commit is contained in:
Will Jones
2023-06-08 16:07:06 -07:00
committed by GitHub
parent a56b65db84
commit fed33a51d5
14 changed files with 417 additions and 51 deletions

View File

@@ -22,8 +22,21 @@ def connect(uri: URI) -> LanceDBConnection:
uri: str or Path
The uri of the database.
Examples
--------
For a local directory, provide a path for the database:
>>> import lancedb
>>> db = lancedb.connect("~/.lancedb")
For object storage, use a URI prefix:
>>> db = lancedb.connect("s3://my-bucket/lancedb")
Returns
-------
A connection to a LanceDB database.
conn : LanceDBConnection
A connection to a LanceDB database.
"""
return LanceDBConnection(uri)

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@@ -0,0 +1,20 @@
import builtins
import os
import pytest
# import lancedb so we don't have to in every example
import lancedb
@pytest.fixture(autouse=True)
def doctest_setup(monkeypatch, tmpdir):
# disable color for doctests so we don't have to include
# escape codes in docstrings
monkeypatch.setitem(os.environ, "NO_COLOR", "1")
# Explicitly set the column width
monkeypatch.setitem(os.environ, "COLUMNS", "80")
# Work in a temporary directory
monkeypatch.chdir(tmpdir)

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@@ -17,12 +17,74 @@ import pandas as pd
def contextualize(raw_df: pd.DataFrame) -> Contextualizer:
"""Create a Contextualizer object for the given DataFrame.
Used to create context windows.
Used to create context windows. Context windows are rolling subsets of text
data.
The input text column should already be separated into rows that will be the
unit of the window. So to create a context window over tokens, start with
a DataFrame with one token per row. To create a context window over sentences,
start with a DataFrame with one sentence per row.
Examples
--------
>>> from lancedb.context import contextualize
>>> import pandas as pd
>>> data = pd.DataFrame({
... 'token': ['The', 'quick', 'brown', 'fox', 'jumped', 'over',
... 'the', 'lazy', 'dog', 'I', 'love', 'sandwiches'],
... 'document_id': [1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2]
... })
``window`` determines how many rows to include in each window. In our case
this how many tokens, but depending on the input data, it could be sentences,
paragraphs, messages, etc.
>>> contextualize(data).window(3).stride(1).text_col('token').to_df()
token document_id
0 The quick brown 1
1 quick brown fox 1
2 brown fox jumped 1
3 fox jumped over 1
4 jumped over the 1
5 over the lazy 1
6 the lazy dog 1
7 lazy dog I 1
8 dog I love 1
>>> contextualize(data).window(7).stride(1).text_col('token').to_df()
token document_id
0 The quick brown fox jumped over the 1
1 quick brown fox jumped over the lazy 1
2 brown fox jumped over the lazy dog 1
3 fox jumped over the lazy dog I 1
4 jumped over the lazy dog I love 1
``stride`` determines how many rows to skip between each window start. This can
be used to reduce the total number of windows generated.
>>> contextualize(data).window(4).stride(2).text_col('token').to_df()
token document_id
0 The quick brown fox 1
2 brown fox jumped over 1
4 jumped over the lazy 1
6 the lazy dog I 1
``groupby`` determines how to group the rows. For example, we would like to have
context windows that don't cross document boundaries. In this case, we can
pass ``document_id`` as the group by.
>>> contextualize(data).window(4).stride(2).text_col('token').groupby('document_id').to_df()
token document_id
0 The quick brown fox 1
2 brown fox jumped over 1
4 jumped over the lazy 1
"""
return Contextualizer(raw_df)
class Contextualizer:
"""Create context windows from a DataFrame. See [lancedb.context.contextualize][]."""
def __init__(self, raw_df):
self._text_col = None
self._groupby = None

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@@ -28,6 +28,31 @@ from .util import get_uri_scheme, get_uri_location
class LanceDBConnection:
"""
A connection to a LanceDB database.
Parameters
----------
uri: str or Path
The root uri of the database.
Examples
--------
>>> import lancedb
>>> db = lancedb.connect("./.lancedb")
>>> db.create_table("my_table", data=[{"vector": [1.1, 1.2], "b": 2},
... {"vector": [0.5, 1.3], "b": 4}])
LanceTable(my_table)
>>> db.create_table("another_table", data=[{"vector": [0.4, 0.4], "b": 6}])
LanceTable(another_table)
>>> db.table_names()
['another_table', 'my_table']
>>> len(db)
2
>>> db["my_table"]
LanceTable(my_table)
>>> "my_table" in db
True
>>> db.drop_table("my_table")
>>> db.drop_table("another_table")
"""
def __init__(self, uri: URI):
@@ -48,7 +73,8 @@ class LanceDBConnection:
Returns
-------
A list of table names.
list of str
A list of table names.
"""
try:
filesystem, path = fs.FileSystem.from_uri(self.uri)
@@ -103,7 +129,73 @@ class LanceDBConnection:
Returns
-------
A LanceTable object representing the table.
LanceTable
A reference to the newly created table.
Examples
--------
Can create with list of tuples or dictionaries:
>>> import lancedb
>>> db = lancedb.connect("./.lancedb")
>>> data = [{"vector": [1.1, 1.2], "lat": 45.5, "long": -122.7},
... {"vector": [0.2, 1.8], "lat": 40.1, "long": -74.1}]
>>> db.create_table("my_table", data)
LanceTable(my_table)
>>> db["my_table"].head()
pyarrow.Table
vector: fixed_size_list<item: float>[2]
child 0, item: float
lat: double
long: double
----
vector: [[[1.1,1.2],[0.2,1.8]]]
lat: [[45.5,40.1]]
long: [[-122.7,-74.1]]
You can also pass a pandas DataFrame:
>>> import pandas as pd
>>> data = pd.DataFrame({
... "vector": [[1.1, 1.2], [0.2, 1.8]],
... "lat": [45.5, 40.1],
... "long": [-122.7, -74.1]
... })
>>> db.create_table("table2", data)
LanceTable(table2)
>>> db["table2"].head()
pyarrow.Table
vector: fixed_size_list<item: float>[2]
child 0, item: float
lat: double
long: double
----
vector: [[[1.1,1.2],[0.2,1.8]]]
lat: [[45.5,40.1]]
long: [[-122.7,-74.1]]
Data is converted to Arrow before being written to disk. For maximum
control over how data is saved, either provide the PyArrow schema to
convert to or else provide a PyArrow table directly.
>>> custom_schema = pa.schema([
... pa.field("vector", pa.list_(pa.float32(), 2)),
... pa.field("lat", pa.float32()),
... pa.field("long", pa.float32())
... ])
>>> db.create_table("table3", data, schema = custom_schema)
LanceTable(table3)
>>> db["table3"].head()
pyarrow.Table
vector: fixed_size_list<item: float>[2]
child 0, item: float
lat: float
long: float
----
vector: [[[1.1,1.2],[0.2,1.8]]]
lat: [[45.5,40.1]]
long: [[-122.7,-74.1]]
"""
if data is not None:
tbl = LanceTable.create(self, name, data, schema, mode=mode)

View File

@@ -29,7 +29,31 @@ def with_embeddings(
wrap_api: bool = True,
show_progress: bool = False,
batch_size: int = 1000,
):
) -> pa.Table:
"""Add a vector column to a table using the given embedding function.
The new columns will be called "vector".
Parameters
----------
func : Callable
A function that takes a list of strings and returns a list of vectors.
data : pa.Table or pd.DataFrame
The data to add an embedding column to.
column : str, default "text"
The name of the column to use as input to the embedding function.
wrap_api : bool, default True
Whether to wrap the embedding function in a retry and rate limiter.
show_progress : bool, default False
Whether to show a progress bar.
batch_size : int, default 1000
The number of row values to pass to each call of the embedding function.
Returns
-------
pa.Table
The input table with a new column called "vector" containing the embeddings.
"""
func = EmbeddingFunction(func)
if wrap_api:
func = func.retry().rate_limit()

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@@ -68,6 +68,11 @@ def populate_index(index: tantivy.Index, table: LanceTable, fields: List[str]) -
The table to index
fields : List[str]
List of fields to index
Returns
-------
int
The number of rows indexed
"""
# first check the fields exist and are string or large string type
for name in fields:

View File

@@ -11,6 +11,7 @@
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import annotations
from typing import Literal
import numpy as np
import pandas as pd
@@ -22,6 +23,24 @@ from .common import VECTOR_COLUMN_NAME
class LanceQueryBuilder:
"""
A builder for nearest neighbor queries for LanceDB.
Examples
--------
>>> import lancedb
>>> data = [{"vector": [1.1, 1.2], "b": 2},
... {"vector": [0.5, 1.3], "b": 4},
... {"vector": [0.4, 0.4], "b": 6},
... {"vector": [0.4, 0.4], "b": 10}]
>>> db = lancedb.connect("./.lancedb")
>>> table = db.create_table("my_table", data=data)
>>> (table.search([0.4, 0.4])
... .metric("cosine")
... .where("b < 10")
... .select(["b"])
... .limit(2)
... .to_df())
b vector score
0 6 [0.4, 0.4] 0.0
"""
def __init__(self, table: "lancedb.table.LanceTable", query: np.ndarray):
@@ -44,7 +63,8 @@ class LanceQueryBuilder:
Returns
-------
The LanceQueryBuilder object.
LanceQueryBuilder
The LanceQueryBuilder object.
"""
self._limit = limit
return self
@@ -59,7 +79,8 @@ class LanceQueryBuilder:
Returns
-------
The LanceQueryBuilder object.
LanceQueryBuilder
The LanceQueryBuilder object.
"""
self._columns = columns
return self
@@ -74,22 +95,24 @@ class LanceQueryBuilder:
Returns
-------
The LanceQueryBuilder object.
LanceQueryBuilder
The LanceQueryBuilder object.
"""
self._where = where
return self
def metric(self, metric: str) -> LanceQueryBuilder:
def metric(self, metric: Literal["L2", "cosine"]) -> LanceQueryBuilder:
"""Set the distance metric to use.
Parameters
----------
metric: str
The distance metric to use. By default "l2" is used.
metric: "L2" or "cosine"
The distance metric to use. By default "L2" is used.
Returns
-------
The LanceQueryBuilder object.
LanceQueryBuilder
The LanceQueryBuilder object.
"""
self._metric = metric
return self
@@ -97,6 +120,12 @@ class LanceQueryBuilder:
def nprobes(self, nprobes: int) -> LanceQueryBuilder:
"""Set the number of probes to use.
Higher values will yield better recall (more likely to find vectors if
they exist) at the expense of latency.
See discussion in [Querying an ANN Index][../querying-an-ann-index] for
tuning advice.
Parameters
----------
nprobes: int
@@ -104,13 +133,20 @@ class LanceQueryBuilder:
Returns
-------
The LanceQueryBuilder object.
LanceQueryBuilder
The LanceQueryBuilder object.
"""
self._nprobes = nprobes
return self
def refine_factor(self, refine_factor: int) -> LanceQueryBuilder:
"""Set the refine factor to use.
"""Set the refine factor to use, increasing the number of vectors sampled.
As an example, a refine factor of 2 will sample 2x as many vectors as
requested, re-ranks them, and returns the top half most relevant results.
See discussion in [Querying an ANN Index][querying-an-ann-index] for
tuning advice.
Parameters
----------
@@ -119,7 +155,8 @@ class LanceQueryBuilder:
Returns
-------
The LanceQueryBuilder object.
LanceQueryBuilder
The LanceQueryBuilder object.
"""
self._refine_factor = refine_factor
return self

View File

@@ -47,6 +47,40 @@ def _sanitize_data(data, schema):
class LanceTable:
"""
A table in a LanceDB database.
Examples
--------
Create using [LanceDBConnection.create_table][lancedb.LanceDBConnection.create_table]
(more examples in that method's documentation).
>>> import lancedb
>>> db = lancedb.connect("./.lancedb")
>>> table = db.create_table("my_table", data=[{"vector": [1.1, 1.2], "b": 2}])
>>> table.head()
pyarrow.Table
vector: fixed_size_list<item: float>[2]
child 0, item: float
b: int64
----
vector: [[[1.1,1.2]]]
b: [[2]]
Can append new data with [LanceTable.add][lancedb.table.LanceTable.add].
>>> table.add([{"vector": [0.5, 1.3], "b": 4}])
2
Can query the table with [LanceTable.search][lancedb.table.LanceTable.search].
>>> table.search([0.4, 0.4]).select(["b"]).to_df()
b vector score
0 4 [0.5, 1.3] 0.82
1 2 [1.1, 1.2] 1.13
Search queries are much faster when an index is created. See
[LanceTable.create_index][lancedb.table.LanceTable.create_index].
"""
def __init__(
@@ -64,7 +98,12 @@ class LanceTable:
@property
def schema(self) -> pa.Schema:
"""Return the schema of the table."""
"""Return the schema of the table.
Returns
-------
pa.Schema
A PyArrow schema object."""
return self._dataset.schema
def list_versions(self):
@@ -72,12 +111,39 @@ class LanceTable:
return self._dataset.versions()
@property
def version(self):
def version(self) -> int:
"""Get the current version of the table"""
return self._dataset.version
def checkout(self, version: int):
"""Checkout a version of the table"""
"""Checkout a version of the table. This is an in-place operation.
This allows viewing previous versions of the table.
Parameters
----------
version : int
The version to checkout.
Examples
--------
>>> import lancedb
>>> db = lancedb.connect("./.lancedb")
>>> table = db.create_table("my_table", [{"vector": [1.1, 0.9], "type": "vector"}])
>>> table.version
1
>>> table.to_pandas()
vector type
0 [1.1, 0.9] vector
>>> table.add([{"vector": [0.5, 0.2], "type": "vector"}])
2
>>> table.version
2
>>> table.checkout(1)
>>> table.to_pandas()
vector type
0 [1.1, 0.9] vector
"""
max_ver = max([v["version"] for v in self._dataset.versions()])
if version < 1 or version > max_ver:
raise ValueError(f"Invalid version {version}")
@@ -98,11 +164,20 @@ class LanceTable:
return self._dataset.head(n)
def to_pandas(self) -> pd.DataFrame:
"""Return the table as a pandas DataFrame."""
"""Return the table as a pandas DataFrame.
Returns
-------
pd.DataFrame
"""
return self.to_arrow().to_pandas()
def to_arrow(self) -> pa.Table:
"""Return the table as a pyarrow Table."""
"""Return the table as a pyarrow Table.
Returns
-------
pa.Table"""
return self._dataset.to_table()
@property
@@ -175,7 +250,8 @@ class LanceTable:
Returns
-------
The number of vectors added to the table.
int
The number of vectors in the table.
"""
data = _sanitize_data(data, self.schema)
lance.write_dataset(data, self._dataset_uri, mode=mode)
@@ -193,10 +269,11 @@ class LanceTable:
Returns
-------
A LanceQueryBuilder object representing the query.
Once executed, the query returns selected columns, the vector,
and also the "score" column which is the distance between the query
vector and the returned vector.
LanceQueryBuilder
A query builder object representing the query.
Once executed, the query returns selected columns, the vector,
and also the "score" column which is the distance between the query
vector and the returned vector.
"""
if isinstance(query, str):
# fts

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@@ -37,7 +37,7 @@ repository = "https://github.com/lancedb/lancedb"
[project.optional-dependencies]
tests = [
"pytest", "pytest-mock"
"pytest", "pytest-mock", "doctest"
]
dev = [
"ruff", "pre-commit", "black"

View File

@@ -30,23 +30,13 @@ class MockTable:
@pytest.fixture
def table(tmp_path) -> MockTable:
df = pd.DataFrame(
{
"vector": [[1, 2], [3, 4]],
"id": [1, 2],
"str_field": ["a", "b"],
"float_field": [1.0, 2.0],
}
)
schema = pa.schema(
[
pa.field("vector", pa.list_(pa.float32(), list_size=2)),
pa.field("id", pa.int32()),
pa.field("str_field", pa.string()),
pa.field("float_field", pa.float64()),
]
)
lance.write_dataset(df, tmp_path, schema)
df = pa.table({
"vector": pa.array([[1, 2], [3, 4]], type=pa.list_(pa.float32(), list_size=2)),
"id": pa.array([1, 2]),
"str_field": pa.array(["a", "b"]),
"float_field": pa.array([1.0, 2.0]),
})
lance.write_dataset(df, tmp_path)
return MockTable(tmp_path)
@@ -65,7 +55,7 @@ def test_query_builder_with_filter(table):
def test_query_builder_with_metric(table):
query = [4, 8]
df_default = LanceQueryBuilder(table, query).to_df()
df_l2 = LanceQueryBuilder(table, query).metric("l2").to_df()
df_l2 = LanceQueryBuilder(table, query).metric("L2").to_df()
tm.assert_frame_equal(df_default, df_l2)
df_cosine = LanceQueryBuilder(table, query).metric("cosine").limit(1).to_df()