ConcatField - Aggregation for Python's Agate library, to concatenate every value in a column into a single string

gistfile1.txt

class ConcatField(agate.Aggregation):
    """
    Concatenate every value in a column into a string.

    :param column_name:
        The name of any column.
    """
    def __init__(self, column_name, sep='|'):
        self._column_name = column_name
        self._sep = sep

    def get_aggregate_data_type(self, table):
        return agate.Text()

    def validate(self, table):
    	pass
        # column = table.columns[self._column_name]

        # if not isinstance(column.data_type, Text):
        #     raise DataTypeError('MaxLength can only be applied to columns containing Text data.')

    def run(self, table):
        """
        :returns:
            :class:`str`.
        """
        column = table.columns[self._column_name]

        values = [str(v) if v != None else '' for v in column.values()]
        s = self._sep.join(values)

        return s