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USearch 是一个更小、更快的单文件向量搜索引擎
USearch 的基础功能与 FAISS 完全相同，如果你曾研究过近似最近邻搜索，其接口应该会让你感到熟悉。FAISS 是高性能向量搜索引擎领域广泛认可的标准。USearch 和 FAISS 都采用相同的 HNSW 算法，但两者在设计理念上存在显著差异。USearch 在不牺牲性能的前提下，体积紧凑、兼容性广，主要专注于用户自定义指标并减少依赖项。 
pip install -qU  usearch langchain-community
我们希望使用 OpenAIEmbeddings，因此需要获取 OpenAI API Key。 
import getpass
import os

if "OPENAI_API_KEY" not in os.environ:
    os.environ["OPENAI_API_KEY"] = getpass.getpass("OpenAI API Key:")

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

from langchain_community.document_loaders import TextLoader

loader = TextLoader("../../../extras/modules/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()

db = USearch.from_documents(docs, embeddings)

query = "What did the president say about Ketanji Brown Jackson"
docs = db.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.

​
带分数的相似度搜索

similarity_search_with_score 方法不仅可以返回文档，还可以返回查询与文档之间的距离分数。返回的距离分数为 L2 距离，因此分数越低越好。 
docs_and_scores = db.similarity_search_with_score(query)

docs_and_scores[0]

(Document(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. \n\nTonight, 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. \n\nOne of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court. \n\nAnd 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.', metadata={'source': '../../../extras/modules/state_of_the_union.txt'}),
 0.1845687)
在 GitHub 上编辑此页面 或 提交问题。
将这些文档连接 到 Claude、VSCode 等工具，通过 MCP 获取实时解答。