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Camel to snake

Class for converting DataFrame column names from camel case to snake case.

koheesio.spark.transformations.camel_to_snake.camel_to_snake_re module-attribute #

camel_to_snake_re = compile('([a-z0-9])([A-Z])')

koheesio.spark.transformations.camel_to_snake.CamelToSnakeTransformation #

Converts column names from camel case to snake cases

Parameters:

Name Type Description Default
columns Optional[ListOfColumns]

The column or columns to convert. If no columns are specified, all columns will be converted. A list of columns or a single column can be specified. For example: ["column1", "column2"] or "column1"

 None
Example

input_df:

camelCaseColumn snake_case_column
... ... 
output_df = CamelToSnakeTransformation(
    column="camelCaseColumn"
).transform(input_df)

output_df:

camel_case_column snake_case_column
... ...

In this example, the column camelCaseColumn is converted to camel_case_column.

Note: the data in the columns is not changed, only the column names.

execute #

execute() -> Output
Source code in src/koheesio/spark/transformations/camel_to_snake.py 
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def execute(self) -> ColumnsTransformation.Output:
    _df = self.df

    # Prepare columns input:
    columns = list(self.get_columns())

    if SPARK_MINOR_VERSION < 3.4:
        for column in columns:
            _df = _df.withColumnRenamed(column, convert_camel_to_snake(column))

    else:
        # Rename columns using toDF for Spark versions >= 3.4
        # Note: toDF requires all column names to be specified
        new_column_names = []
        for column in _df.columns:
            if column in columns:
                new_column_names.append(convert_camel_to_snake(column))
                continue
            new_column_names.append(column)
        _df = _df.toDF(*new_column_names)

    self.output.df = _df

koheesio.spark.transformations.camel_to_snake.convert_camel_to_snake #

convert_camel_to_snake(name: str) -> str

Converts a string from camelCase to snake_case.

Parameters:

name : str The string to be converted.

Returns:

str The converted string in snake_case.

Source code in src/koheesio/spark/transformations/camel_to_snake.py 
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def convert_camel_to_snake(name: str) -> str:
    """
    Converts a string from camelCase to snake_case.

    Parameters:
    ----------
    name : str
        The string to be converted.

    Returns:
    --------
    str
        The converted string in snake_case.
    """
    return camel_to_snake_re.sub(r"\1_\2", name).lower()