枚举解析器

本笔记本演示如何使用枚举输出解析器。

from langchain.output_parsers.enum import EnumOutputParser

from enum import Enum


class Colors(Enum):
    RED = "red"
    GREEN = "green"
    BLUE = "blue"

parser = EnumOutputParser(enum=Colors)

parser.parse("red")

<Colors.RED: 'red'>

# Can handle spaces
parser.parse(" green")

<Colors.GREEN: 'green'>

# And new lines
parser.parse("blue\n")

<Colors.BLUE: 'blue'>

# And raises errors when appropriate
parser.parse("yellow")

---------------------------------------------------------------------------

ValueError                                Traceback (most recent call last)

File ~/workplace/langchain/langchain/output_parsers/enum.py:25, in EnumOutputParser.parse(self, response)
     24 try:
---> 25     return self.enum(response.strip())
     26 except ValueError:


File ~/.pyenv/versions/3.9.1/lib/python3.9/enum.py:315, in EnumMeta.__call__(cls, value, names, module, qualname, type, start)
    314 if names is None:  # simple value lookup
--> 315     return cls.__new__(cls, value)
    316 # otherwise, functional API: we're creating a new Enum type


File ~/.pyenv/versions/3.9.1/lib/python3.9/enum.py:611, in Enum.__new__(cls, value)
    610 if result is None and exc is None:
--> 611     raise ve_exc
    612 elif exc is None:


ValueError: 'yellow' is not a valid Colors


During handling of the above exception, another exception occurred:


OutputParserException                     Traceback (most recent call last)

Cell In[8], line 2
      1 # And raises errors when appropriate
----> 2 parser.parse("yellow")


File ~/workplace/langchain/langchain/output_parsers/enum.py:27, in EnumOutputParser.parse(self, response)
     25     return self.enum(response.strip())
     26 except ValueError:
---> 27     raise OutputParserException(
     28         f"Response '{response}' is not one of the "
     29         f"expected values: {self._valid_values}"
     30     )


OutputParserException: Response 'yellow' is not one of the expected values: ['red', 'green', 'blue']