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scikit-learn

scikit-learn 是一个开源的机器学习算法集合，包括一些 k 最近邻 的实现。SKLearnVectorStore 封装了此实现，并增加了以 json、bson（二进制 json）或 Apache Parquet 格式持久化向量存储的可能性。

本笔记本展示了如何使用 SKLearnVectorStore 向量数据库。

您需要通过运行 pip install -qU langchain-community 来安装 langchain-community 以使用此集成

%pip install --upgrade --quiet  scikit-learn

# # if you plan to use bson serialization, install also:
%pip install --upgrade --quiet  bson

# # if you plan to use parquet serialization, install also:
%pip install --upgrade --quiet  pandas pyarrow

要使用 OpenAI embeddings，您需要一个 OpenAI 密钥。您可以在 https://platform.openai.com/account/api-keys 获取，也可以随意使用任何其他 embeddings。

import os
from getpass import getpass

if "OPENAI_API_KEY" not in os.environ:
    os.environ["OPENAI_API_KEY"] = getpass("Enter your OpenAI key:")

基本用法​

加载一个示例文档语料库​

from langchain_community.document_loaders import TextLoader
from langchain_community.vectorstores import SKLearnVectorStore
from langchain_openai import OpenAIEmbeddings
from langchain_text_splitters import CharacterTextSplitter

loader = TextLoader("../../how_to/state_of_the_union.txt")
documents = loader.load()
text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
docs = text_splitter.split_documents(documents)
embeddings = OpenAIEmbeddings()

创建 SKLearnVectorStore、索引文档语料库并运行示例查询​

import tempfile

persist_path = os.path.join(tempfile.gettempdir(), "union.parquet")

vector_store = SKLearnVectorStore.from_documents(
    documents=docs,
    embedding=embeddings,
    persist_path=persist_path,  # persist_path and serializer are optional
    serializer="parquet",
)

query = "What did the president say about Ketanji Brown Jackson"
docs = vector_store.similarity_search(query)
print(docs[0].page_content)
Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you’re at it, pass the Disclose Act so Americans can know who is funding our elections. 

Tonight, I’d like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service. 

One of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court. 

And I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation’s top legal minds, who will continue Justice Breyer’s legacy of excellence.

保存和加载向量存储​

vector_store.persist()
print("Vector store was persisted to", persist_path)
Vector store was persisted to /var/folders/6r/wc15p6m13nl_nl_n_xfqpc5c0000gp/T/union.parquet
vector_store2 = SKLearnVectorStore(
    embedding=embeddings, persist_path=persist_path, serializer="parquet"
)
print("A new instance of vector store was loaded from", persist_path)
A new instance of vector store was loaded from /var/folders/6r/wc15p6m13nl_nl_n_xfqpc5c0000gp/T/union.parquet
docs = vector_store2.similarity_search(query)
print(docs[0].page_content)
Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you’re at it, pass the Disclose Act so Americans can know who is funding our elections. 

Tonight, I’d like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service. 

One of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court. 

And I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation’s top legal minds, who will continue Justice Breyer’s legacy of excellence.

清理​

os.remove(persist_path)