LangChain \u662f\u4e00\u4e2a\u7528\u4e8e\u5f00\u53d1\u7531\u8bed\u8a00\u6a21\u578b\u9a71\u52a8\u7684\u5e94\u7528\u7a0b\u5e8f\u7684\u5f3a\u5927\u6846\u67b6\u3002\u672c\u6587\u5c06\u5e26\u4f60\u4ece\u96f6\u5f00\u59cb\u5b66\u4e60 LangChain\u3002<\/p>\n
## \u4ec0\u4e48\u662f LangChain\uff1f
\nLangChain \u662f\u4e00\u4e2a\u5f00\u6e90\u6846\u67b6\uff0c\u4e13\u95e8\u7528\u4e8e\u6784\u5efa\u57fa\u4e8e\u5927\u8bed\u8a00\u6a21\u578b\uff08LLM\uff09\u7684\u5e94\u7528\u7a0b\u5e8f\u3002\u5b83\u63d0\u4f9b\u4e86\u6a21\u5757\u5316\u7684\u7ec4\u4ef6\uff0c\u8ba9\u4f60\u53ef\u4ee5\u8f7b\u677e\u5730\u7ec4\u5408\u548c\u5b9a\u5236\u5404\u79cd LLM \u529f\u80fd\u3002<\/p>\n
**\u6838\u5fc3\u7279\u70b9\uff1a**
\n– \u6a21\u5757\u5316\u8bbe\u8ba1\uff1a\u6bcf\u4e2a\u7ec4\u4ef6\u90fd\u53ef\u4ee5\u72ec\u7acb\u4f7f\u7528\u548c\u7ec4\u5408
\n– \u94fe\u5f0f\u8c03\u7528\uff1a\u5c06\u591a\u4e2a\u7ec4\u4ef6\u4e32\u8054\u8d77\u6765\u5f62\u6210\u590d\u6742\u7684\u5904\u7406\u6d41\u7a0b
\n– \u8bb0\u5fc6\u7ba1\u7406\uff1a\u81ea\u52a8\u5904\u7406\u5bf9\u8bdd\u5386\u53f2\u548c\u4e0a\u4e0b\u6587
\n– \u5de5\u5177\u8c03\u7528\uff1a\u8ba9 LLM \u80fd\u591f\u8c03\u7528\u5916\u90e8\u5de5\u5177\u548c API
\n– \u6570\u636e\u96c6\u6210\uff1a\u8f7b\u677e\u96c6\u6210\u5404\u79cd\u6570\u636e\u6e90<\/p>\n
## \u5feb\u901f\u5f00\u59cb<\/p>\n
### \u5b89\u88c5
\n“`bash
\npip install langchain langchain-openai langchain-community
\n“`<\/p>\n
### Hello World
\n“`python
\nfrom langchain_openai import ChatOpenAI
\nfrom langchain_core.messages import HumanMessage<\/p>\n
llm = ChatOpenAI(model=”gpt-4o-mini”, temperature=0.7)
\nmessage = HumanMessage(content=”\u4f60\u597d\uff0c\u4ecb\u7ecd\u4e00\u4e0b\u4f60\u81ea\u5df1”)
\nresponse = llm.invoke([message])
\nprint(response.content)
\n“`<\/p>\n
## \u6838\u5fc3\u7ec4\u4ef6<\/p>\n
### 1. \u8bed\u8a00\u6a21\u578b\uff08LLMs\uff09
\n“`python
\nfrom langchain_openai import ChatOpenAI
\nfrom langchain_anthropic import ChatAnthropic
\nfrom langchain_google_genai import ChatGoogleGenerativeAI<\/p>\n
openai_llm = ChatOpenAI(model=”gpt-4o”)
\nanthropic_llm = ChatAnthropic(model=”claude-3-5-sonnet-20241022″)
\ngoogle_llm = ChatGoogleGenerativeAI(model=”gemini-1.5-pro”)
\n“`<\/p>\n
### 2. \u63d0\u793a\u6a21\u677f\uff08Prompt Templates\uff09
\n“`python
\nfrom langchain_core.prompts import ChatPromptTemplate<\/p>\n
prompt = ChatPromptTemplate.from_messages([
\n (“system”, “\u4f60\u662f\u4e00\u4e2a{role}\u52a9\u624b\u3002”),
\n (“user”, “{input}”)
\n])
\nformatted_prompt = prompt.invoke({“role”: “\u7f16\u7a0b”, “input”: “\u5982\u4f55\u5b66\u4e60 Python\uff1f”})
\n“`<\/p>\n
### 3. \u94fe\uff08Chains\uff09
\n“`python
\nllm = ChatOpenAI(model=”gpt-4o-mini”)
\nprompt = ChatPromptTemplate.from_template(“\u7528\u7b80\u5355\u7684\u8bdd\u89e3\u91ca{topic}”)
\nchain = prompt | llm | StrOutputParser()
\nresult = chain.invoke({“topic”: “\u91cf\u5b50\u8ba1\u7b97”})
\n“`<\/p>\n
### 4. \u8bb0\u5fc6\uff08Memory\uff09
\n“`python
\nfrom langchain_core.chat_history import InMemoryChatMessageHistory
\nfrom langchain_core.messages import HumanMessage, SystemMessage<\/p>\n
history = InMemoryChatMessageHistory()
\nhistory.add_message(HumanMessage(content=”\u6211\u53eb\u5c0f\u660e”))
\nhistory.add_message(SystemMessage(content=”\u4f60\u597d\u5c0f\u660e\uff01”))
\n“`<\/p>\n
## \u5b9e\u6218\u793a\u4f8b\uff1a\u7b80\u5355\u95ee\u7b54\u7cfb\u7edf
\n“`python
\nfrom langchain_openai import ChatOpenAI
\nfrom langchain_core.prompts import ChatPromptTemplate
\nfrom langchain_core.output_parsers import StrOutputParser<\/p>\n
prompt = ChatPromptTemplate.from_messages([
\n (“system”, “\u4f60\u662f\u4e00\u4e2a\u6709\u5e2e\u52a9\u7684\u52a9\u624b\u3002”),
\n (“user”, “{question}”)
\n])
\nllm = ChatOpenAI(model=”gpt-4o-mini”)
\nchain = prompt | llm | StrOutputParser()<\/p>\n
result = chain.invoke({“question”: “\u4ec0\u4e48\u662f LangChain\uff1f”})
\nprint(result)
\n“`<\/p>\n","protected":false},"excerpt":{"rendered":"
LangChain \u662f\u4e00\u4e2a\u7528\u4e8e\u5f00\u53d1\u7531\u8bed\u8a00\u6a21\u578b\u9a71\u52a8\u7684\u5e94\u7528\u7a0b\u5e8f\u7684\u5f3a\u5927\u6846\u67b6\u3002\u672c\u6587\u5c06\u5e26\u4f60\u4ece\u96f6\u5f00\u59cb\u5b66\u4e60 LangChai […]<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"zakra_page_container_layout":"customizer","zakra_page_sidebar_layout":"customizer","zakra_remove_content_margin":false,"zakra_sidebar":"customizer","zakra_transparent_header":"customizer","zakra_logo":0,"zakra_main_header_style":"default","zakra_menu_item_color":"","zakra_menu_item_hover_color":"","zakra_menu_item_active_color":"","zakra_menu_active_style":"","zakra_page_header":true,"footnotes":""},"categories":[7],"tags":[],"class_list":["post-13","post","type-post","status-publish","format-standard","hentry","category-langchain"],"_links":{"self":[{"href":"https:\/\/gmrea.com\/index.php?rest_route=\/wp\/v2\/posts\/13","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gmrea.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gmrea.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/gmrea.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13"}],"version-history":[{"count":0,"href":"https:\/\/gmrea.com\/index.php?rest_route=\/wp\/v2\/posts\/13\/revisions"}],"wp:attachment":[{"href":"https:\/\/gmrea.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gmrea.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gmrea.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}