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Python wrapper for reverse ordering of a value.
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| class Reverse(object): | |
| ''' | |
| Wrapper for reverse ordering of a value. | |
| Usage: | |
| array = [1, 2, 3, 4] | |
| array.sort(key=Reverse) | |
| # [4, 3, 2, 1] | |
| from collections import namedtuple | |
| Student = namedtuple('Student', ['name', 'mark']) | |
| array = [Student('John', 4), Student('Jeane', 4), Student('John', 3)] | |
| array.sort(key=lambda student: (Reverse(student.mark), student.name)) | |
| # [Student('Jeane', 4), Student('John', 4), Student('John', 3)] | |
| ''' | |
| def __init__(self, value): | |
| self.value = value | |
| def __repr__(self): | |
| return f'Reverse({self.value!r})' | |
| def _type_guard(self, sign, other): | |
| if not isinstance(other, Reverse): | |
| raise TypeError( | |
| "'{}' not supported between instances of '{}' and '{}'" | |
| .format(sign, 'Reverse', type(other).__name__) | |
| ) | |
| def __lt__(self, other): | |
| self._type_guard('<', other) | |
| return other.value < self.value | |
| def __gt__(self, other): | |
| self._type_guard('>', other) | |
| return other.value > self.value | |
| def __le__(self, other): | |
| self._type_guard('<=', other) | |
| return other.value <= self.value | |
| def __ge__(self, other): | |
| self._type_guard('>=', other) | |
| return other.value >= self.value | |
| def __eq__(self, other): | |
| self._type_guard('==', other) | |
| return other.value == self.value | |
| def __neq__(self, other): | |
| self._type_guard('!=', other) | |
| return other.value != self.value |
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