LangChain LangGraph 教程:安装 作者:马育民 • 2026-05-24 21:44 • 阅读:10000 # 安装 langgraph 依赖 langchain,调用大模型依赖 langchain-openai,所以通常安装这3个库 ```bash pip install -U langgraph langchain langchain-openai ``` **参数解释:** - `-U`:安装最新版,如果存在旧版就自动更新 ### 测试是否安装成功 下面例子是对话循环 ```python from typing import TypedDict, List, Dict, Any from langgraph.graph import StateGraph, END from langchain_openai import ChatOpenAI # 1. 定义状态 class ChatState(TypedDict): messages: List[Dict[str, Any]] # 2. 初始化 LLM llm = ChatOpenAI(model="gpt-3.5-turbo") # 3. 定义节点 def call_llm(state: ChatState) -> ChatState: messages = state["messages"] response = llm.invoke(messages) return {"messages": messages + [{"role": "assistant", "content": response.content}]} # 4. 定义条件边:是否结束 def is_end(state: ChatState) -> str: if len(state["messages"]) > 3: # 最多3轮对话 return END return "continue" # 5. 构建图 graph = StateGraph(ChatState) graph.add_node("llm", call_llm) graph.set_entry_point("llm") graph.add_conditional_edges("llm", is_end, {"continue": "llm", END: END}) # 6. 编译并运行 app = graph.compile() result = app.invoke({"messages": [{"role": "user", "content": "Hello!"}]}) print(result["messages"][-1]["content"]) ``` 原文出处:http://malaoshi.top/show_1GW3N4rjleqE.html