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Mark Pilgrim
103 lines
3.5 KiB
HTML
103 lines
3.5 KiB
HTML
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<title>Advanced Classes - Dive into Python 3</title>
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<p>You are here: <a href=index.html>Home</a> <span>‣</span> <a href=table-of-contents.html#advanced-classes>Dive Into Python 3</a> <span>‣</span>
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<p id=level>Difficulty level: <span title=advanced>♦♦♦♦♢</span>
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<h1>Advanced Classes</h1>
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<blockquote class=q>
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<p><span>❝</span> FIXME <span>❞</span><br>— FIXME
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</blockquote>
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<p id=toc>
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<h2 id=divingin>Diving In</h2>
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<p class=f>FIXME
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<h2 id=ordereddict>Ordered Dictionary: Not An Oxymoron</h2>
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<p class=d>[<a href=examples/ordereddict.py>download <code>ordereddict.py</code></a>]
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<pre><code>import collections
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import itertools
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class OrderedDict(dict, collections.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 itertools.zip_longest(self.items(), other.items()))
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return dict.__eq__(self, other)</code></pre>
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<h2 id=implementing-fractions>Implementing Fractions</h2>
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<p class=nav><a rel=prev class=todo><span>☜</span></a> <a rel=next class=todo><span>☞</span></a>
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<p class=c>© 2001–9 <a href=about.html>Mark Pilgrim</a>
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