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Parsers

RegexExtractor

Bases: BaseComponent

Simple class for extracting text from a document using a regex pattern.

Parameters:

Name Type Description Default
pattern List[str]

The regex pattern(s) to use.

 required
output_map dict

A mapping from extracted text to the desired output. Defaults to None.

 required
Source code in libs\kotaemon\kotaemon\parsers\regex_extractor.py 
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class RegexExtractor(BaseComponent):
    """
    Simple class for extracting text from a document using a regex pattern.

    Args:
        pattern (List[str]): The regex pattern(s) to use.
        output_map (dict, optional): A mapping from extracted text to the
            desired output. Defaults to None.
    """

    class Config:
        middleware_switches = {"theflow.middleware.CachingMiddleware": False}

    pattern: list[str]
    output_map: dict[str, str] | Callable[[str], str] = Param(
        default_callback=lambda *_: {}
    )

    def __init__(self, pattern: str | list[str], **kwargs):
        if isinstance(pattern, str):
            pattern = [pattern]
        super().__init__(pattern=pattern, **kwargs)

    @staticmethod
    def run_raw_static(pattern: str, text: str) -> list[str]:
        """
        Finds all non-overlapping occurrences of a pattern in a string.

        Parameters:
            pattern (str): The regular expression pattern to search for.
            text (str): The input string to search in.

        Returns:
            List[str]: A list of all non-overlapping occurrences of the pattern in the
                string.
        """
        return re.findall(pattern, text)

    @staticmethod
    def map_output(text, output_map) -> str:
        """
        Maps the given `text` to its corresponding value in the `output_map` dictionary.

        Parameters:
            text (str): The input text to be mapped.
            output_map (dict): A dictionary containing mapping of input text to output
                values.

        Returns:
            str: The corresponding value from the `output_map` if `text` is found in the
                dictionary, otherwise returns the original `text`.
        """
        if not output_map:
            return text

        if isinstance(output_map, dict):
            return output_map.get(text, text)

        return output_map(text)

    def run_raw(self, text: str) -> ExtractorOutput:
        """
        Matches the raw text against the pattern and rans the output mapping, returning
            an instance of ExtractorOutput.

        Args:
            text (str): The raw text to be processed.

        Returns:
            ExtractorOutput: The processed output as a list of ExtractorOutput.
        """
        output: list[str] = sum(
            [self.run_raw_static(p, text) for p in self.pattern], []
        )
        output = [self.map_output(text, self.output_map) for text in output]

        return ExtractorOutput(
            text=output[0] if output else "",
            matches=output,
            metadata={"origin": "RegexExtractor"},
        )

    def run(
        self, text: str | list[str] | Document | list[Document]
    ) -> list[ExtractorOutput]:
        """Match the input against a pattern and return the output for each input

        Parameters:
            text: contains the input string to be processed

        Returns:
            A list contains the output ExtractorOutput for each input

        Example:
            ```pycon
            >>> document1 = Document(...)
            >>> document2 = Document(...)
            >>> document_batch = [document1, document2]
            >>> batch_output = self(document_batch)
            >>> print(batch_output)
            [output1_document1, output1_document2]
            ```
        """
        # TODO: this conversion seems common
        input_: list[str] = []
        if not isinstance(text, list):
            text = [text]

        for item in text:
            if isinstance(item, str):
                input_.append(item)
            elif isinstance(item, Document):
                input_.append(item.text)
            else:
                raise ValueError(
                    f"Invalid input type {type(item)}, should be str or Document"
                )

        output = []
        for each_input in input_:
            output.append(self.run_raw(each_input))

        return output

run_raw_static staticmethod 

1
run_raw_static(pattern, text)

Finds all non-overlapping occurrences of a pattern in a string.

Parameters:

Name Type Description Default
pattern str

The regular expression pattern to search for.

 required
text str

The input string to search in.

 required

Returns:

Type Description
list[str]

List[str]: A list of all non-overlapping occurrences of the pattern in the string.
Source code in libs\kotaemon\kotaemon\parsers\regex_extractor.py 
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@staticmethod
def run_raw_static(pattern: str, text: str) -> list[str]:
    """
    Finds all non-overlapping occurrences of a pattern in a string.

    Parameters:
        pattern (str): The regular expression pattern to search for.
        text (str): The input string to search in.

    Returns:
        List[str]: A list of all non-overlapping occurrences of the pattern in the
            string.
    """
    return re.findall(pattern, text)

map_output staticmethod 

1
map_output(text, output_map)

Maps the given text to its corresponding value in the output_map dictionary.

Parameters:

Name Type Description Default
text str

The input text to be mapped.

 required
output_map dict

A dictionary containing mapping of input text to output values.

 required

Returns:

Name Type Description
str str

The corresponding value from the output_map if text is found in the dictionary, otherwise returns the original text.
Source code in libs\kotaemon\kotaemon\parsers\regex_extractor.py 
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@staticmethod
def map_output(text, output_map) -> str:
    """
    Maps the given `text` to its corresponding value in the `output_map` dictionary.

    Parameters:
        text (str): The input text to be mapped.
        output_map (dict): A dictionary containing mapping of input text to output
            values.

    Returns:
        str: The corresponding value from the `output_map` if `text` is found in the
            dictionary, otherwise returns the original `text`.
    """
    if not output_map:
        return text

    if isinstance(output_map, dict):
        return output_map.get(text, text)

    return output_map(text)

run_raw 

1
run_raw(text)

Matches the raw text against the pattern and rans the output mapping, returning an instance of ExtractorOutput.

Parameters:

Name Type Description Default
text str

The raw text to be processed.

 required

Returns:

Name Type Description
ExtractorOutput ExtractorOutput

The processed output as a list of ExtractorOutput.
Source code in libs\kotaemon\kotaemon\parsers\regex_extractor.py 
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def run_raw(self, text: str) -> ExtractorOutput:
    """
    Matches the raw text against the pattern and rans the output mapping, returning
        an instance of ExtractorOutput.

    Args:
        text (str): The raw text to be processed.

    Returns:
        ExtractorOutput: The processed output as a list of ExtractorOutput.
    """
    output: list[str] = sum(
        [self.run_raw_static(p, text) for p in self.pattern], []
    )
    output = [self.map_output(text, self.output_map) for text in output]

    return ExtractorOutput(
        text=output[0] if output else "",
        matches=output,
        metadata={"origin": "RegexExtractor"},
    )

run 

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run(text)

Match the input against a pattern and return the output for each input

Parameters:

Name Type Description Default
text str | list[str] | Document | list[Document]

contains the input string to be processed

 required

Returns:

Type Description
list[ExtractorOutput]

A list contains the output ExtractorOutput for each input
Example 
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>>> document1 = Document(...)
>>> document2 = Document(...)
>>> document_batch = [document1, document2]
>>> batch_output = self(document_batch)
>>> print(batch_output)
[output1_document1, output1_document2]
Source code in libs\kotaemon\kotaemon\parsers\regex_extractor.py 
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def run(
    self, text: str | list[str] | Document | list[Document]
) -> list[ExtractorOutput]:
    """Match the input against a pattern and return the output for each input

    Parameters:
        text: contains the input string to be processed

    Returns:
        A list contains the output ExtractorOutput for each input

    Example:
        ```pycon
        >>> document1 = Document(...)
        >>> document2 = Document(...)
        >>> document_batch = [document1, document2]
        >>> batch_output = self(document_batch)
        >>> print(batch_output)
        [output1_document1, output1_document2]
        ```
    """
    # TODO: this conversion seems common
    input_: list[str] = []
    if not isinstance(text, list):
        text = [text]

    for item in text:
        if isinstance(item, str):
            input_.append(item)
        elif isinstance(item, Document):
            input_.append(item.text)
        else:
            raise ValueError(
                f"Invalid input type {type(item)}, should be str or Document"
            )

    output = []
    for each_input in input_:
        output.append(self.run_raw(each_input))

    return output