diff --git a/Lib/collections.py b/Lib/collections.py index 4ac50d8a66d..3329f08d62b 100644 --- a/Lib/collections.py +++ b/Lib/collections.py @@ -298,16 +298,16 @@ class Counter(dict): or multiset. Elements are stored as dictionary keys and their counts are stored as dictionary values. - >>> c = Counter('abracadabra') # count elements from a string + >>> c = Counter('abcdeabcdabcaba') # count elements from a string >>> c.most_common(3) # three most common elements - [('a', 5), ('r', 2), ('b', 2)] + [('a', 5), ('b', 4), ('c', 3)] >>> sorted(c) # list all unique elements - ['a', 'b', 'c', 'd', 'r'] + ['a', 'b', 'c', 'd', 'e'] >>> ''.join(sorted(c.elements())) # list elements with repetitions - 'aaaaabbcdrr' + 'aaaaabbbbcccdde' >>> sum(c.values()) # total of all counts - 11 + 15 >>> c['a'] # count of letter 'a' 5 @@ -315,8 +315,8 @@ class Counter(dict): ... c[elem] += 1 # by adding 1 to each element's count >>> c['a'] # now there are seven 'a' 7 - >>> del c['r'] # remove all 'r' - >>> c['r'] # now there are zero 'r' + >>> del c['b'] # remove all 'b' + >>> c['b'] # now there are zero 'b' 0 >>> d = Counter('simsalabim') # make another counter @@ -355,6 +355,7 @@ class Counter(dict): >>> c = Counter(a=4, b=2) # a new counter from keyword args ''' + super().__init__() self.update(iterable, **kwds) def __missing__(self, key): @@ -366,8 +367,8 @@ class Counter(dict): '''List the n most common elements and their counts from the most common to the least. If n is None, then list all element counts. - >>> Counter('abracadabra').most_common(3) - [('a', 5), ('r', 2), ('b', 2)] + >>> Counter('abcdeabcdabcaba').most_common(3) + [('a', 5), ('b', 4), ('c', 3)] ''' # Emulate Bag.sortedByCount from Smalltalk @@ -433,7 +434,7 @@ class Counter(dict): for elem, count in iterable.items(): self[elem] = count + self_get(elem, 0) else: - dict.update(self, iterable) # fast path when counter is empty + super().update(iterable) # fast path when counter is empty else: self_get = self.get for elem in iterable: @@ -445,10 +446,13 @@ class Counter(dict): 'Like dict.copy() but returns a Counter instance instead of a dict.' return Counter(self) + def __reduce__(self): + return self.__class__, (dict(self),) + def __delitem__(self, elem): 'Like dict.__delitem__() but does not raise KeyError for missing values.' if elem in self: - dict.__delitem__(self, elem) + super().__delitem__(elem) def __repr__(self): if not self: