LangChain Model I/O

TIP

Model I/O 统一了不同 LLM 的调用接口，支持提示模板和输出解析。

支持的模型

# OpenAI
from langchain_openai import ChatOpenAI
llm = ChatOpenAI(model="gpt-4", temperature=0)

# Ollama（本地）
from langchain_ollama import ChatOllama
llm = ChatOllama(model="qwen2:7b")

提示模板

from langchain.prompts import ChatPromptTemplate

prompt = ChatPromptTemplate.from_messages([
    ("system", "你是一个{role}助手"),
    ("human", "{input}")
])

少样本示例

from langchain.prompts import FewShotPromptTemplate

examples = [
    {"input": "高兴", "output": "开心、愉悦"},
    {"input": "悲伤", "output": "难过、伤心"},
]

example_prompt = PromptTemplate.from_template(
    "输入: {input}\n输出: {output}"
)

few_shot_prompt = FewShotPromptTemplate(
    examples=examples,
    example_prompt=example_prompt,
    prefix="请给出同义词:",
    suffix="输入: {input}\n输出:",
    input_variables=["input"]
)