38 lines
1.3 KiB
Python
38 lines
1.3 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 Number
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from agate.utils import default
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class Count(Aggregation):
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"""
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Count occurences of a value or values.
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This aggregation can be used in three ways:
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1. If no arguments are specified, then it will count the number of rows in the table.
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2. If only :code:`column_name` is specified, then it will count the number of non-null values in that column.
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3. If both :code:`column_name` and :code:`value` are specified, then it will count occurrences of a specific value.
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:param column_name:
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The column containing the values to be counted.
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:param value:
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Any value to be counted, including :code:`None`.
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"""
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def __init__(self, column_name=None, value=default):
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self._column_name = column_name
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self._value = value
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def get_aggregate_data_type(self, table):
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return Number()
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def run(self, table):
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if self._column_name is not None:
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if self._value is not default:
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return table.columns[self._column_name].values().count(self._value)
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else:
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return len(table.columns[self._column_name].values_without_nulls())
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else:
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return len(table.rows)
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