Files
all-in-rag/code/C1/01_langchain_example.py
2026-05-12 09:41:56 +08:00

76 lines
2.2 KiB
Python

import os
# hugging face镜像设置,如果国内环境无法使用启用该设置
# os.environ['HF_ENDPOINT'] = 'https://hf-mirror.com'
from dotenv import load_dotenv
from langchain_community.document_loaders import UnstructuredMarkdownLoader
from langchain_text_splitters import RecursiveCharacterTextSplitter
from langchain_huggingface import HuggingFaceEmbeddings
from langchain_core.vectorstores import InMemoryVectorStore
from langchain_core.prompts import ChatPromptTemplate
from langchain_openai import ChatOpenAI
load_dotenv()
markdown_path = "../../data/C1/markdown/easy-rl-chapter1.md"
# 加载本地markdown文件
loader = UnstructuredMarkdownLoader(markdown_path)
docs = loader.load()
# 文本分块
text_splitter = RecursiveCharacterTextSplitter()
chunks = text_splitter.split_documents(docs)
# 中文嵌入模型
embeddings = HuggingFaceEmbeddings(
model_name="BAAI/bge-small-zh-v1.5",
model_kwargs={'device': 'cpu'},
encode_kwargs={'normalize_embeddings': True}
)
# 构建向量存储
vectorstore = InMemoryVectorStore(embeddings)
vectorstore.add_documents(chunks)
# 提示词模板
prompt = ChatPromptTemplate.from_template("""请根据下面提供的上下文信息来回答问题。
请确保你的回答完全基于这些上下文。
如果上下文中没有足够的信息来回答问题,请直接告知:“抱歉,我无法根据提供的上下文找到相关信息来回答此问题。”
上下文:
{context}
问题: {question}
回答:"""
)
# 配置大语言模型
# 使用 AIHubmix
llm = ChatOpenAI(
model="glm-4.7-flash-free",
temperature=0.7,
max_tokens=4096,
api_key=os.getenv("DEEPSEEK_API_KEY"),
base_url="https://aihubmix.com/v1"
)
# llm = ChatOpenAI(
# model="deepseek-chat",
# temperature=0.7,
# max_tokens=4096,
# api_key=os.getenv("DEEPSEEK_API_KEY"),
# base_url="https://api.deepseek.com"
# )
# 用户查询
question = "文中举了哪些例子?"
# 在向量存储中查询相关文档
retrieved_docs = vectorstore.similarity_search(question, k=3)
docs_content = "\n\n".join(doc.page_content for doc in retrieved_docs)
answer = llm.invoke(prompt.format(question=question, context=docs_content))
print(answer)