106 lines
2.8 KiB
Python
106 lines
2.8 KiB
Python
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import decimal
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import numbers
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import random
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import sys
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import numpy as np
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import pandas as pd
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from pandas.core.arrays import ExtensionArray
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from pandas.core.dtypes.base import ExtensionDtype
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class DecimalDtype(ExtensionDtype):
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type = decimal.Decimal
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name = 'decimal'
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na_value = decimal.Decimal('NaN')
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@classmethod
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def construct_from_string(cls, string):
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if string == cls.name:
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return cls()
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else:
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raise TypeError("Cannot construct a '{}' from "
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"'{}'".format(cls, string))
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class DecimalArray(ExtensionArray):
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dtype = DecimalDtype()
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def __init__(self, values):
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assert all(isinstance(v, decimal.Decimal) for v in values)
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values = np.asarray(values, dtype=object)
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self._data = values
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# Some aliases for common attribute names to ensure pandas supports
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# these
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self._items = self.data = self._data
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# those aliases are currently not working due to assumptions
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# in internal code (GH-20735)
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# self._values = self.values = self.data
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@classmethod
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def _from_sequence(cls, scalars):
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return cls(scalars)
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@classmethod
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def _from_factorized(cls, values, original):
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return cls(values)
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def __getitem__(self, item):
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if isinstance(item, numbers.Integral):
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return self._data[item]
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else:
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return type(self)(self._data[item])
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def take(self, indexer, allow_fill=False, fill_value=None):
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from pandas.api.extensions import take
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data = self._data
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if allow_fill and fill_value is None:
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fill_value = self.dtype.na_value
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result = take(data, indexer, fill_value=fill_value,
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allow_fill=allow_fill)
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return self._from_sequence(result)
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def copy(self, deep=False):
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if deep:
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return type(self)(self._data.copy())
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return type(self)(self)
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def __setitem__(self, key, value):
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if pd.api.types.is_list_like(value):
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value = [decimal.Decimal(v) for v in value]
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else:
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value = decimal.Decimal(value)
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self._data[key] = value
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def __len__(self):
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return len(self._data)
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def __repr__(self):
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return 'DecimalArray({!r})'.format(self._data)
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@property
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def nbytes(self):
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n = len(self)
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if n:
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return n * sys.getsizeof(self[0])
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return 0
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def isna(self):
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return np.array([x.is_nan() for x in self._data], dtype=bool)
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@property
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def _na_value(self):
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return decimal.Decimal('NaN')
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@classmethod
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def _concat_same_type(cls, to_concat):
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return cls(np.concatenate([x._data for x in to_concat]))
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def make_data():
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return [decimal.Decimal(random.random()) for _ in range(100)]
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