enterprise-kb-rag/2.2_LangChain基础知识/13_output_parser_list.py

from pathlib import Path
import sys

sys.path.append(str(Path(__file__).resolve().parents[1]))

from _chapter2_config import get_chat_model, print_dependency_hint


try:
    from langchain_core.output_parsers import CommaSeparatedListOutputParser
    from langchain_core.prompts import ChatPromptTemplate
except ModuleNotFoundError as exc:
    print_dependency_hint(exc)
    raise SystemExit(1)


def main() -> None:
    try:
        model = get_chat_model(temperature=0)
    except ModuleNotFoundError as exc:
        print_dependency_hint(exc)
        raise SystemExit(1)

    parser = CommaSeparatedListOutputParser()
    format_instructions = parser.get_format_instructions()
    prompt = ChatPromptTemplate.from_template(
        "用中文列出{topic}的五个最重要特点。\n{format_instructions}"
    )

    chain = prompt | model | parser
    result = chain.invoke(
        {
            "topic": "大模型",
            "format_instructions": format_instructions,
        }
    )
    print(result)


if __name__ == "__main__":
    main()