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DocArrayHnswSearch

DocArrayHnswSearch是由Docarray提供的轻量级文档索引实现，完全在本地运行，最适合小到中型数据集。它将向量存储在hnswlib中的磁盘上，并将所有其他数据存储在SQLite中。

本笔记本展示了如何使用与DocArrayHnswSearch相关的功能。

设置​

取消下面的单元格的注释以安装docarray并获取/设置您的OpenAI API密钥（如果您尚未这样做）。

# !pip install "docarray[hnswlib]"
# 获取OpenAI令牌：https://platform.openai.com/account/api-keys

# import os
# from getpass import getpass

# OPENAI_API_KEY = getpass()

# os.environ["OPENAI_API_KEY"] = OPENAI_API_KEY

使用DocArrayHnswSearch​

from langchain.embeddings.openai import OpenAIEmbeddings
from langchain.text_splitter import CharacterTextSplitter
from langchain.vectorstores import DocArrayHnswSearch
from langchain.document_loaders import TextLoader
documents = TextLoader("../../../state_of_the_union.txt").load()
text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
docs = text_splitter.split_documents(documents)

embeddings = OpenAIEmbeddings()

db = DocArrayHnswSearch.from_documents(
    docs, embeddings, work_dir="hnswlib_store/", n_dim=1536
)

相似度搜索​

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.

带有分数的相似度搜索​

返回的距离分数是余弦距离。因此，较低的分数更好。

docs = db.similarity_search_with_score(query)
docs[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={}),
     0.36962226)
import shutil

# 删除目录
shutil.rmtree("hnswlib_store")