class Counter(dict):
- '''Dict subclass for counting hashable objects. Sometimes called a bag
+ """Dict subclass for counting hashable objects. Sometimes called a bag
or multiset. Elements are stored as dictionary keys and their counts
are stored as dictionary values.
>>> Counter('zyzygy')
Counter({'y': 3, 'z': 2, 'g': 1})
- '''
+ """
def __init__(self, iterable=None, **kwds):
- '''Create a new, empty Counter object. And if given, count elements
+ """Create a new, empty Counter object. And if given, count elements
from an input iterable. Or, initialize the count from another mapping
of elements to their counts.
>>> c = Counter({'a': 4, 'b': 2}) # a new counter from a mapping
>>> c = Counter(a=4, b=2) # a new counter from keyword args
- '''
+ """
self.update(iterable, **kwds)
def __missing__(self, key):
return 0
def most_common(self, n=None):
- '''List the n most common elements and their counts from the most
+ """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)]
- '''
+ """
if n is None:
return sorted(self.iteritems(), key=itemgetter(1), reverse=True)
return nlargest(n, self.iteritems(), key=itemgetter(1))
def elements(self):
- '''Iterator over elements repeating each as many times as its count.
+ """Iterator over elements repeating each as many times as its count.
>>> c = Counter('ABCABC')
>>> sorted(c.elements())
If an element's count has been set to zero or is a negative number,
elements() will ignore it.
- '''
+ """
for elem, count in self.iteritems():
for _ in repeat(None, count):
yield elem
@classmethod
def fromkeys(cls, iterable, v=None):
raise NotImplementedError(
- 'Counter.fromkeys() is undefined. Use Counter(iterable) instead.')
+ "Counter.fromkeys() is undefined. Use Counter(iterable) instead."
+ )
def update(self, iterable=None, **kwds):
- '''Like dict.update() but add counts instead of replacing them.
+ """Like dict.update() but add counts instead of replacing them.
Source can be an iterable, a dictionary, or another Counter instance.
>>> c['h'] # four 'h' in which, witch, and watch
4
- '''
+ """
if iterable is not None:
- if hasattr(iterable, 'iteritems'):
+ if hasattr(iterable, "iteritems"):
if self:
self_get = self.get
for elem, count in iterable.iteritems():
self.update(kwds)
def copy(self):
- 'Like dict.copy() but returns a Counter instance instead of a dict.'
+ "Like dict.copy() but returns a Counter instance instead of a dict."
return Counter(self)
def __delitem__(self, elem):
- 'Like dict.__delitem__() but does not raise KeyError for missing values.'
+ "Like dict.__delitem__() but does not raise KeyError for missing values."
if elem in self:
dict.__delitem__(self, elem)
def __repr__(self):
if not self:
- return '%s()' % self.__class__.__name__
- items = ', '.join(map('%r: %r'.__mod__, self.most_common()))
- return '%s({%s})' % (self.__class__.__name__, items)
+ return "%s()" % self.__class__.__name__
+ items = ", ".join(map("%r: %r".__mod__, self.most_common()))
+ return "%s({%s})" % (self.__class__.__name__, items)
# Multiset-style mathematical operations discussed in:
# Knuth TAOCP Volume II section 4.6.3 exercise 19
# c += Counter()
def __add__(self, other):
- '''Add counts from two counters.
+ """Add counts from two counters.
>>> Counter('abbb') + Counter('bcc')
Counter({'b': 4, 'c': 2, 'a': 1})
- '''
+ """
if not isinstance(other, Counter):
return NotImplemented
result = Counter()
return result
def __sub__(self, other):
- ''' Subtract count, but keep only results with positive counts.
+ """Subtract count, but keep only results with positive counts.
>>> Counter('abbbc') - Counter('bccd')
Counter({'b': 2, 'a': 1})
- '''
+ """
if not isinstance(other, Counter):
return NotImplemented
result = Counter()
return result
def __or__(self, other):
- '''Union is the maximum of value in either of the input counters.
+ """Union is the maximum of value in either of the input counters.
>>> Counter('abbb') | Counter('bcc')
Counter({'b': 3, 'c': 2, 'a': 1})
- '''
+ """
if not isinstance(other, Counter):
return NotImplemented
_max = max
return result
def __and__(self, other):
- ''' Intersection is the minimum of corresponding counts.
+ """Intersection is the minimum of corresponding counts.
>>> Counter('abbb') & Counter('bcc')
Counter({'b': 1})
- '''
+ """
if not isinstance(other, Counter):
return NotImplemented
_min = min
return result
-if __name__ == '__main__':
+if __name__ == "__main__":
import doctest
+
print(doctest.testmod())
Code Review / integration / test.git / blobdiff