NumberedListOutputParser Class — langchain Architecture

Architecture documentation for the NumberedListOutputParser class in list.py from the langchain codebase.

Class python

Entity Profile

Dependency Diagram

graph TD
  b8940fcc_465e_32f4_d9e6_c01e04edca69["NumberedListOutputParser"]
  137024f5_2b01_9c8f_64f4_357c533282c7["ListOutputParser"]
  b8940fcc_465e_32f4_d9e6_c01e04edca69 -->|extends| 137024f5_2b01_9c8f_64f4_357c533282c7
  39460b97_96ad_60ff_34e4_145e3ec6b305["list.py"]
  b8940fcc_465e_32f4_d9e6_c01e04edca69 -->|defined in| 39460b97_96ad_60ff_34e4_145e3ec6b305
  9f87fa85_5293_af74_ea1b_1e6e9e4cf423["get_format_instructions()"]
  b8940fcc_465e_32f4_d9e6_c01e04edca69 -->|method| 9f87fa85_5293_af74_ea1b_1e6e9e4cf423
  9d18cade_0cbf_cb62_89a9_adf6b090d483["parse()"]
  b8940fcc_465e_32f4_d9e6_c01e04edca69 -->|method| 9d18cade_0cbf_cb62_89a9_adf6b090d483
  7ca90d0f_a7b9_6724_8d59_6dcc04ef152a["parse_iter()"]
  b8940fcc_465e_32f4_d9e6_c01e04edca69 -->|method| 7ca90d0f_a7b9_6724_8d59_6dcc04ef152a
  7e118702_1e5a_322e_f3eb_07ba9fef3ef1["_type()"]
  b8940fcc_465e_32f4_d9e6_c01e04edca69 -->|method| 7e118702_1e5a_322e_f3eb_07ba9fef3ef1

Relationship Graph

Source Code

libs/core/langchain_core/output_parsers/list.py lines 188–218

class NumberedListOutputParser(ListOutputParser):
    """Parse a numbered list."""

    pattern: str = r"\d+\.\s([^\n]+)"
    """The pattern to match a numbered list item."""

    @override
    def get_format_instructions(self) -> str:
        return (
            "Your response should be a numbered list with each item on a new line. "
            "For example: \n\n1. foo\n\n2. bar\n\n3. baz"
        )

    def parse(self, text: str) -> list[str]:
        """Parse the output of an LLM call.

        Args:
            text: The output of an LLM call.

        Returns:
            A list of strings.
        """
        return re.findall(self.pattern, text)

    @override
    def parse_iter(self, text: str) -> Iterator[re.Match]:
        return re.finditer(self.pattern, text)

    @property
    def _type(self) -> str:
        return "numbered-list"