41 lines
1.2 KiB
Python
41 lines
1.2 KiB
Python
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#!/usr/bin/env python
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from agate.aggregations.base import Aggregation
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from agate.data_types import Date, DateTime, Number
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from agate.exceptions import DataTypeError
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class Max(Aggregation):
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"""
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Find the maximum value in a column.
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This aggregation can be applied to columns containing :class:`.Date`,
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:class:`.DateTime`, or :class:`.Number` data.
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:param column_name:
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The name of the column to be searched.
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"""
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def __init__(self, column_name):
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self._column_name = column_name
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def get_aggregate_data_type(self, table):
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column = table.columns[self._column_name]
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if (isinstance(column.data_type, Number) or
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isinstance(column.data_type, Date) or
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isinstance(column.data_type, DateTime)):
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return column.data_type
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def validate(self, table):
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column = table.columns[self._column_name]
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if not (isinstance(column.data_type, Number) or
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isinstance(column.data_type, Date) or
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isinstance(column.data_type, DateTime)):
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raise DataTypeError('Min can only be applied to columns containing DateTime orNumber data.')
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def run(self, table):
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column = table.columns[self._column_name]
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return max(column.values_without_nulls())
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