37 lines
1.0 KiB
Python
37 lines
1.0 KiB
Python
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#!/usr/bin/env python
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from agate.aggregations.base import Aggregation
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class Summary(Aggregation):
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"""
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Apply an arbitrary function to a column.
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:param column_name:
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The name of a column to be summarized.
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:param data_type:
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The return type of this aggregation.
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:param func:
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A function which will be passed the column for processing.
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:param cast:
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If :code:`True`, each return value will be cast to the specified
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:code:`data_type` to ensure it is valid. Only disable this if you are
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certain your summary always returns the correct type.
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"""
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def __init__(self, column_name, data_type, func, cast=True):
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self._column_name = column_name
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self._data_type = data_type
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self._func = func
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self._cast = cast
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def get_aggregate_data_type(self, table):
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return self._data_type
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def run(self, table):
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v = self._func(table.columns[self._column_name])
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if self._cast:
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v = self._data_type.cast(v)
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return v
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