langchain demo

m0_475064502026-04-29 11:26

环境要求：

python3.10以上，3.13以下。我用的是3.11

可以用anoconda创建环境，conda create -n py311 python=3.11

环境安装完成后：

选择anaconda powershell prompt

执行：

conda activate py311

pip install -U langchain

pip install -U langchain-openai

pip install -U langchain-anthropic

在系统环境变量中添加：

变量名：OPENAI_API_KEY

变量值：填你的阿里百炼的

打开pycharm 或者vscode

创建python文件

python 复制代码

from langchain.agents import create_agent
from langchain_openai import ChatOpenAI
import json
from langchain_core.messages import message_to_dict

def get_weather(city: str) -> str:
    """Get weather for a given city."""
    return f"It's always sunny in {city}!"

llm = ChatOpenAI(model="qwen-turbo", base_url="https://dashscope.aliyuncs.com/compatible-mode/v1")

agent = create_agent(
    model=llm,
    tools=[get_weather],
    system_prompt="You are a helpful assistant",
)

result = agent.invoke(
    {"messages": [{"role": "user", "content": "What's the weather in San Francisco?"}]}
)
payload = {
    "messages": [message_to_dict(message) for message in result["messages"]]
}
print(json.dumps(payload, ensure_ascii=False, indent=2))

执行python demo2.py