249 lines
7.8 KiB
Python
249 lines
7.8 KiB
Python
class MergeDict(object):
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"""
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A simple class for creating new "virtual" dictionaries that actualy look
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up values in more than one dictionary, passed in the constructor.
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"""
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def __init__(self, *dicts):
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self.dicts = dicts
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def __getitem__(self, key):
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for dict in self.dicts:
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try:
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return dict[key]
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except KeyError:
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pass
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raise KeyError
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def __contains__(self, key):
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return self.has_key(key)
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def get(self, key, default=None):
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try:
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return self[key]
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except KeyError:
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return default
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def getlist(self, key):
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for dict in self.dicts:
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try:
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return dict.getlist(key)
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except KeyError:
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pass
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raise KeyError
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def items(self):
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item_list = []
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for dict in self.dicts:
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item_list.extend(dict.items())
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return item_list
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def has_key(self, key):
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for dict in self.dicts:
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if dict.has_key(key):
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return True
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return False
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class SortedDict(dict):
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"A dictionary that keeps its keys in the order in which they're inserted."
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def __init__(self, data=None):
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if data is None: data = {}
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dict.__init__(self, data)
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self.keyOrder = data.keys()
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def __setitem__(self, key, value):
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dict.__setitem__(self, key, value)
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if key not in self.keyOrder:
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self.keyOrder.append(key)
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def __delitem__(self, key):
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dict.__delitem__(self, key)
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self.keyOrder.remove(key)
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def __iter__(self):
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for k in self.keyOrder:
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yield k
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def items(self):
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return zip(self.keyOrder, self.values())
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def keys(self):
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return self.keyOrder[:]
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def values(self):
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return [dict.__getitem__(self, k) for k in self.keyOrder]
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def update(self, dict):
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for k, v in dict.items():
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self.__setitem__(k, v)
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def setdefault(self, key, default):
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if key not in self.keyOrder:
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self.keyOrder.append(key)
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return dict.setdefault(self, 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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class MultiValueDictKeyError(KeyError):
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pass
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class MultiValueDict(dict):
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"""
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A subclass of dictionary customized to handle multiple values for the same key.
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>>> d = MultiValueDict({'name': ['Adrian', 'Simon'], 'position': ['Developer']})
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>>> d['name']
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'Simon'
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>>> d.getlist('name')
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['Adrian', 'Simon']
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>>> d.get('lastname', 'nonexistent')
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'nonexistent'
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>>> d.setlist('lastname', ['Holovaty', 'Willison'])
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This class exists to solve the irritating problem raised by cgi.parse_qs,
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which returns a list for every key, even though most Web forms submit
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single name-value pairs.
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"""
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def __init__(self, key_to_list_mapping=()):
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dict.__init__(self, key_to_list_mapping)
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def __repr__(self):
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return "<MultiValueDict: %s>" % dict.__repr__(self)
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def __getitem__(self, key):
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"""
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Returns the last data value for this key, or [] if it's an empty list;
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raises KeyError if not found.
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"""
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try:
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list_ = dict.__getitem__(self, key)
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except KeyError:
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raise MultiValueDictKeyError, "Key %r not found in %r" % (key, self)
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try:
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return list_[-1]
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except IndexError:
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return []
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def __setitem__(self, key, value):
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dict.__setitem__(self, key, [value])
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def __copy__(self):
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return self.__class__(dict.items(self))
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def __deepcopy__(self, memo=None):
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import copy
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if memo is None: memo = {}
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result = self.__class__()
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memo[id(self)] = result
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for key, value in dict.items(self):
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dict.__setitem__(result, copy.deepcopy(key, memo), copy.deepcopy(value, memo))
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return result
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def get(self, key, default=None):
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"Returns the default value if the requested data doesn't exist"
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try:
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val = self[key]
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except KeyError:
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return default
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if val == []:
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return default
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return val
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def getlist(self, key):
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"Returns an empty list if the requested data doesn't exist"
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try:
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return dict.__getitem__(self, key)
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except KeyError:
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return []
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def setlist(self, key, list_):
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dict.__setitem__(self, key, list_)
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def setdefault(self, key, default=None):
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if key not in self:
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self[key] = default
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return self[key]
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def setlistdefault(self, key, default_list=()):
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if key not in self:
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self.setlist(key, default_list)
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return self.getlist(key)
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def appendlist(self, key, value):
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"Appends an item to the internal list associated with key"
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self.setlistdefault(key, [])
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dict.__setitem__(self, key, self.getlist(key) + [value])
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def items(self):
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"""
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Returns a list of (key, value) pairs, where value is the last item in
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the list associated with the key.
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"""
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return [(key, self[key]) for key in self.keys()]
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def lists(self):
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"Returns a list of (key, list) pairs."
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return dict.items(self)
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def values(self):
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"Returns a list of the last value on every key list."
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return [self[key] for key in self.keys()]
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def copy(self):
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"Returns a copy of this object."
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return self.__deepcopy__()
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def update(self, *args, **kwargs):
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"update() extends rather than replaces existing key lists. Also accepts keyword args."
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if len(args) > 1:
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raise TypeError, "update expected at most 1 arguments, got %d", len(args)
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if args:
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other_dict = args[0]
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if isinstance(other_dict, MultiValueDict):
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for key, value_list in other_dict.lists():
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self.setlistdefault(key, []).extend(value_list)
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else:
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try:
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for key, value in other_dict.items():
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self.setlistdefault(key, []).append(value)
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except TypeError:
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raise ValueError, "MultiValueDict.update() takes either a MultiValueDict or dictionary"
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for key, value in kwargs.iteritems():
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self.setlistdefault(key, []).append(value)
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class DotExpandedDict(dict):
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"""
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A special dictionary constructor that takes a dictionary in which the keys
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may contain dots to specify inner dictionaries. It's confusing, but this
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example should make sense.
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>>> d = DotExpandedDict({'person.1.firstname': ['Simon'],
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'person.1.lastname': ['Willison'],
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'person.2.firstname': ['Adrian'],
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'person.2.lastname': ['Holovaty']})
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>>> d
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{'person': {'1': {'lastname': ['Willison'], 'firstname': ['Simon']},
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'2': {'lastname': ['Holovaty'], 'firstname': ['Adrian']}}}
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>>> d['person']
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{'1': {'firstname': ['Simon'], 'lastname': ['Willison'],
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'2': {'firstname': ['Adrian'], 'lastname': ['Holovaty']}
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>>> d['person']['1']
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{'firstname': ['Simon'], 'lastname': ['Willison']}
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# Gotcha: Results are unpredictable if the dots are "uneven":
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>>> DotExpandedDict({'c.1': 2, 'c.2': 3, 'c': 1})
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>>> {'c': 1}
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"""
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def __init__(self, key_to_list_mapping):
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for k, v in key_to_list_mapping.items():
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current = self
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bits = k.split('.')
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for bit in bits[:-1]:
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current = current.setdefault(bit, {})
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# Now assign value to current position
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try:
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current[bits[-1]] = v
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except TypeError: # Special-case if current isn't a dict.
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current = {bits[-1] : v}
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