Daniel Poelzleithner
13 years ago
3 changed files with 188 additions and 41 deletions
@ -0,0 +1,116 @@
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class SortedDict(dict): |
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""" |
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A dictionary that keeps its keys in the order in which they're inserted. |
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""" |
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def __new__(cls, *args, **kwargs): |
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instance = super(SortedDict, cls).__new__(cls, *args, **kwargs) |
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instance.keyOrder = [] |
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return instance |
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def __init__(self, data=None): |
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if data is None: |
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data = {} |
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elif isinstance(data, GeneratorType): |
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# Unfortunately we need to be able to read a generator twice. Once |
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# to get the data into self with our super().__init__ call and a |
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# second time to setup keyOrder correctly |
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data = list(data) |
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super(SortedDict, self).__init__(data) |
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if isinstance(data, dict): |
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self.keyOrder = data.keys() |
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else: |
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self.keyOrder = [] |
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for key, value in data: |
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if key not in self.keyOrder: |
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self.keyOrder.append(key) |
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def __deepcopy__(self, memo): |
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return self.__class__([(key, deepcopy(value, memo)) |
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for key, value in self.iteritems()]) |
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def __setitem__(self, key, value): |
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if key not in self: |
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self.keyOrder.append(key) |
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super(SortedDict, self).__setitem__(key, value) |
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def __delitem__(self, key): |
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super(SortedDict, self).__delitem__(key) |
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self.keyOrder.remove(key) |
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def __iter__(self): |
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return iter(self.keyOrder) |
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def pop(self, k, *args): |
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result = super(SortedDict, self).pop(k, *args) |
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try: |
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self.keyOrder.remove(k) |
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except ValueError: |
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# Key wasn't in the dictionary in the first place. No problem. |
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pass |
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return result |
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def popitem(self): |
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result = super(SortedDict, self).popitem() |
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self.keyOrder.remove(result[0]) |
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return result |
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def items(self): |
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return zip(self.keyOrder, self.values()) |
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def iteritems(self): |
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for key in self.keyOrder: |
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yield key, self[key] |
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def keys(self): |
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return self.keyOrder[:] |
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def iterkeys(self): |
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return iter(self.keyOrder) |
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def values(self): |
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return map(self.__getitem__, self.keyOrder) |
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def itervalues(self): |
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for key in self.keyOrder: |
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yield self[key] |
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def update(self, dict_): |
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for k, v in dict_.iteritems(): |
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self[k] = v |
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def setdefault(self, key, default): |
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if key not in self: |
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self.keyOrder.append(key) |
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return super(SortedDict, self).setdefault(key, default) |
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def value_for_index(self, index): |
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"""Returns the value of the item at the given zero-based index.""" |
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return self[self.keyOrder[index]] |
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def insert(self, index, key, value): |
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"""Inserts the key, value pair before the item with the given index.""" |
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if key in self.keyOrder: |
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n = self.keyOrder.index(key) |
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del self.keyOrder[n] |
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if n < index: |
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index -= 1 |
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self.keyOrder.insert(index, key) |
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super(SortedDict, self).__setitem__(key, value) |
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def copy(self): |
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"""Returns a copy of this object.""" |
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# This way of initializing the copy means it works for subclasses, too. |
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obj = self.__class__(self) |
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obj.keyOrder = self.keyOrder[:] |
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return obj |
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def __repr__(self): |
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""" |
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Replaces the normal dict.__repr__ with a version that returns the keys |
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in their sorted order. |
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""" |
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return '{%s}' % ', '.join(['%r: %r' % (k, v) for k, v in self.items()]) |
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def clear(self): |
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super(SortedDict, self).clear() |
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self.keyOrder = [] |
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