parseval: A pythonic data validator

parseval is a data validation tool for python. Following are the available parsers:

FieldParser:

Signature: FieldParser(start: int = 0, end: int = 0, quoted: int = 0, enforce_type: bool = True)

Parameters:

• start: Start position of the data in row

• end: End position of the data in row

• quoted: Data quotation options - {0: Not Quoted, 1: Double Quoted, 2: Single Quoted}

• enforce_type: Type conversion control - {True: Output data type will be str, False: Datatype of input will be preserved}. By-default it is set ot True.

Available APIs:

Signature: not_null(default_value: any = None)

Parameters:

• default_value: Default value for a column which should be not null

Signature: value_set(values: typing.List, nullable: bool = True)

Parameters:

• values: Set of valid values for this column
• nullable: If set to True then empty string and None will be treated as valid value, along with the provided value list

Signature: max_value(value: any)

Parameters:

• values: Maximum allowed value for the column

Signature: min_value(value: any)

Parameters:

• values: Minimum allowed value for the column

Signature: range(lower_bound: any, upper_bound: any)

Parameters:

• lower_bound: Minimum allowed value for the column
• upper_bound: Maximum allowed value for the column

Signature: add_func(f: function)

Parameters:

• f: Custom function to be added to the parser

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StringParser:

Signature: StringParser(start: int = 0, end: int = 0, quoted: int = 0, enforce_type: bool = True)

Parameters:

• start: Start position for the column in the row

• end: End position for the column in the row

• quoted: Data quotation options - {0: Not Quoted, 1: Double Quoted, 2: Single Quoted}

• enforce_type: Type conversion control - {True: Output data type will be str, False: Datatype of input will be preserved}. By-default it is set ot True.

Available APIs:

Signature: not_null(default_value: str = None, allow_white_space: bool = False)

Parameters:

• default_value: Default value for a column which should be not null
• allow_white_space: If set to True, whitespaces will not be treated as Null value.

Signature: value_set(values: typing.List[str], nullable: bool = True)

Parameters:

• values: Set of valid values for this column
• nullable: If set to True then empty string and None will be treated as valid value, along with the provided value list

Signature: max_value(value: str)

Parameters:

• values: Maximum allowed value for the column

Signature: min_value(value: str)

Parameters:

• values: Minimum allowed value for the column

Signature: regex_match(pattern: str, nullable=True)

Parameters:

• pattern: Patter to match with the data
• nullable: If set to True then empty string and None will be treated as valid value, along with the values that matches provided pattern

Signature: change_case(case_type: str = 'S')

Parameters:

• case_type: Target case: {'U'/'u': UPPERCASE, 'L'/'l': lowercase, 'S'/'s': Sentence Case}

Signature: range(lower_bound: str, upper_bound: str)

Parameters:

• lower_bound: Minimum allowed value for the column
• upper_bound: Maximum allowed value for the column

Signature: add_func(f: function)

Parameters:

• f: Custom function to be added to the parser

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FloatParser:

Signature: FloatParser(start: int = 0, end: int = 0, quoted: int = 0, enforce_type: bool = True)

Parameters:

• start: Start position for the column in the row

• end: End position for the column in the row

• quoted: Data quotation options - {0: Not Quoted, 1: Double Quoted, 2: Single Quoted}

• enforce_type: Type conversion control - {True: Output data type will be float, False: Datatype of input will be preserved}. By-default it is set ot True.

Available APIs:

Signature: not_null(default_value: float = None)

Parameters:

• default_value: Default value for a column which should be not null

Signature: value_set(values: typing.List[float], nullable: bool = True)

Parameters:

• values: Set of valid values for this column
• nullable: If set to True then empty string and None will be treated as valid value, along with the provided value list

Signature: max_value(value: float)

Parameters:

• values: Maximum allowed value for the column

Signature: min_value(value: float)

Parameters:

• values: Minimum allowed value for the column

Signature: range(lower_bound: float, upper_bound: float)

Parameters:

• lower_bound: Minimum allowed value for the column
• upper_bound: Maximum allowed value for the column

Signature: add_func(f: function)

Parameters:

• f: Custom function to be added to the parser

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IntegerParser:

Signature: IntegerParser(start: int = 0, end: int = 0, quoted: int = 0, enforce_type: bool = True)

Parameters:

• start: Start position for the column in the row

• end: End position for the column in the row

• quoted: Data quotation options - {0: Not Quoted, 1: Double Quoted, 2: Single Quoted}

• enforce_type: Type conversion control - {True: Output data type will be int, False: Datatype of input will be preserved}. By-default it is set ot True.

Available APIs:

Signature: not_null(default_value: int = None)

Parameters:

• default_value: Default value for a column which should be not null

Signature: value_set(values: typing.List[int], nullable: bool = True)

Parameters:

• values: Set of valid values for this column
• nullable: If set to True then empty string and None will be treated as valid value, along with the provided value list

Signature: max_value(value: int)

Parameters:

• values: Maximum allowed value for the column

Signature: min_value(value: int)

Parameters:

• values: Minimum allowed value for the column

Signature: range(lower_bound: int, upper_bound: int)

Parameters:

• lower_bound: Minimum allowed value for the column
• upper_bound: Maximum allowed value for the column

Signature: add_func(f: function)

Parameters:

• f: Custom function to be added to the parser

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BooleanParser:

Signature: BooleanParser(start: int = 0, end: int = 0, quoted: int = 0, enforce_type: bool = True)

Parameters:

• start: Start position for the column in the row

• end: End position for the column in the row

• quoted: Data quotation options - {0: Not Quoted, 1: Double Quoted, 2: Single Quoted}

• enforce_type: Type conversion control - {True: Output data type will be int, False: Datatype of input will be preserved}. By-default it is set ot True.

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DatetimeParser:

Signature: DatetimeParser(start: int = 0, end: int = 0, formats: typing.List =['%Y%m%d', '%Y%m%d%H%M%S'], quoted: int = 0, enforce_type: bool = True)

Parameters:

• start: Start position for the column in the row

• end: End position for the column in the row

• formats: Format of date/datetime used in the input data

• quoted: Data quotation options - {0: Not Quoted, 1: Double Quoted, 2: Single Quoted}

• enforce_type: Type conversion control - {True: Output data type will be datetime.datetime, False: Datatype of input will be preserved}. By-default it is set ot True.

Available APIs:

Signature: not_null(default_value: typing.Union[str, datetime.datetime] = None, format: str = '%Y%m%d%H%M%S')

Parameters:

• default_value: Default value for a column which should be not null
• format: Provided default value format, if a datetime object is provided as default value, then this parameter has no effect.

Signature: value_set(values: typing.List[typing.Union[str, datetime.datetime]], format='%Y%m%d%H%M%S', nullable: bool = True)

Parameters:

• values: Set of valid values for this column
• format: Provided allowed value's format, if a datetime object is provided as allowed value, then this parameter has no effect.
• nullable: If set to True then empty string and None will be treated as valid value, along with the provided value list

Signature: max_value(value: typing.Union[str, datetime.datetime], format: str = '%Y%m%d%H%M%S')

Parameters:

• values: Maximum allowed value for the column
• format: Provided allowed value's format, if a datetime object is provided as allowed value, then this parameter has no effect.

Signature: min_value(value: typing.Union[str, datetime.datetime], format: str = '%Y%m%d%H%M%S')

Parameters:

• values: Minimum allowed value for the column
• format: Provided allowed value's format, if a datetime object is provided as allowed value, then this parameter has no effect.

Signature: range(lower_bound: typing.Union[str, datetime.datetime], upper_bound: typing.Union[str, datetime.datetime], format='%Y%m%d%H%M%S')

Parameters:

• lower_bound: Minimum allowed value for the column
• upper_bound: Maximum allowed value for the column
• format: Provided allowed value's format, if a datetime object is provided as allowed value, then this parameter has no effect.

Signature: add_func(f: function)

Parameters:

• f: Custom function to be added to the parser

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ConstantParser:

Signature: ConstantParser(value)

Parameters:

• value: The parser will always return this value irrespective of the input data and called methods.

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Parser:

Signature: Parser(schema: typing.List[typing.Tuple] = [], input_row_format: str = "delimited", input_row_sep: str = "|", parsed_row_format: str = "delimited", parsed_row_sep: str = None, stop_on_error: int = 0)

Parameters:

• schema: Parser schema for the row.

• input_row_format: Type of row, for json row provide json and for delimited rows provide delimited.

• input_row_sep: Delimiter of input row, not required for input_row_format = "json" scenarios.

• parsed_row_format: Type of output row, if output row is required in json format then provide json and if delimited rows are required provide delimited. Note: "fixed-width" output is not supported.

• parsed_row_sep: Delimiter of output row, not required for parsed_row_format = "json" scenarios.

• stop_on_error: When stop_on_error value is set to 0, the process will stop on encountering an validation error. When stop_on_error value is set to any negative number, the process will skip all erroneous rows and return only valid rows and when stop_on_error value is set to any specific positive number, the process will allow those many erroneous rows, if erroneous rows exceeds that number, the process will fail.

Available APIs:

Signature: parse(data: typing.Union[typing.List[typing.Union[str, typing.Dict]], typing.TextIO])

Parameters:

• data: Input data set

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For detailed installation and usage information please check https://github.com/saumalya75/parseval here.

For any further queries reach out to saumalya75@gmail.com or http://linkedin.com/in/saumalya-sarkar-b3712817b .

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