mirror of
https://github.com/kennethreitz/dive-into-python3.git
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Mark Pilgrim
84 lines
2.5 KiB
Python
84 lines
2.5 KiB
Python
#
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# OrderedDict will be part of the collections module in Python 3.1.
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# This is a standalone version for demonstration purposes only.
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# If you're using Python 3.0, you should upgrade to Python 3.1, then
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# >>> from collections import OrderedDict
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# instead of using this version.
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#
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# Provenance:
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# - PEP 372: OrderedDict http://www.python.org/dev/peps/pep-0372/
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# - Python bug 5397: implement PEP 372 http://bugs.python.org/issue5397
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# - Bug 5397 attachment: http://bugs.python.org/file13231/od7.diff
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#
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from collections import MutableMapping
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from itertools import zip_longest as _zip_longest
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class OrderedDict(dict, MutableMapping):
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def __init__(self, *args, **kwds):
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if len(args) > 1:
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raise TypeError('expected at most 1 arguments')
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if not hasattr(self, '_keys'):
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self._keys = []
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self.update(*args, **kwds)
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def clear(self):
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del self._keys[:]
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dict.clear(self)
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def __setitem__(self, key, value):
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if key not in self:
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self._keys.append(key)
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dict.__setitem__(self, key, value)
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def __delitem__(self, key):
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dict.__delitem__(self, key)
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self._keys.remove(key)
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def __iter__(self):
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return iter(self._keys)
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def __reversed__(self):
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return reversed(self._keys)
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def popitem(self):
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if not self:
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raise KeyError('dictionary is empty')
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key = self._keys.pop()
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value = dict.pop(self, key)
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return key, value
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def __reduce__(self):
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items = [[k, self[k]] for k in self]
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inst_dict = vars(self).copy()
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inst_dict.pop('_keys', None)
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return (self.__class__, (items,), inst_dict)
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setdefault = MutableMapping.setdefault
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update = MutableMapping.update
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pop = MutableMapping.pop
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keys = MutableMapping.keys
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values = MutableMapping.values
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items = MutableMapping.items
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def __repr__(self):
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if not self:
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return '%s()' % (self.__class__.__name__,)
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return '%s(%r)' % (self.__class__.__name__, list(self.items()))
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def copy(self):
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return self.__class__(self)
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@classmethod
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def fromkeys(cls, iterable, value=None):
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d = cls()
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for key in iterable:
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d[key] = value
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return d
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def __eq__(self, other):
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if isinstance(other, OrderedDict):
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return all(p==q for p, q in _zip_longest(self.items(), other.items()))
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return dict.__eq__(self, other)
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