| '''This module implements specialized container datatypes providing |
| alternatives to Python's general purpose built-in containers, dict, |
| list, set, and tuple. |
| |
| * namedtuple factory function for creating tuple subclasses with named fields |
| * deque list-like container with fast appends and pops on either end |
| * Counter dict subclass for counting hashable objects |
| * OrderedDict dict subclass that remembers the order entries were added |
| * defaultdict dict subclass that calls a factory function to supply missing values |
| |
| ''' |
| |
| __all__ = ['Counter', 'deque', 'defaultdict', 'namedtuple', 'OrderedDict'] |
| # For bootstrapping reasons, the collection ABCs are defined in _abcoll.py. |
| # They should however be considered an integral part of collections.py. |
| from _abcoll import * |
| import _abcoll |
| __all__ += _abcoll.__all__ |
| |
| from _collections import deque, defaultdict |
| from operator import itemgetter as _itemgetter, eq as _eq |
| from keyword import iskeyword as _iskeyword |
| import sys as _sys |
| import heapq as _heapq |
| from itertools import repeat as _repeat, chain as _chain, starmap as _starmap |
| from itertools import imap as _imap |
| |
| try: |
| from thread import get_ident as _get_ident |
| except ImportError: |
| from dummy_thread import get_ident as _get_ident |
| |
| |
| ################################################################################ |
| ### OrderedDict |
| ################################################################################ |
| |
| class OrderedDict(dict): |
| 'Dictionary that remembers insertion order' |
| # An inherited dict maps keys to values. |
| # The inherited dict provides __getitem__, __len__, __contains__, and get. |
| # The remaining methods are order-aware. |
| # Big-O running times for all methods are the same as regular dictionaries. |
| |
| # The internal self.__map dict maps keys to links in a doubly linked list. |
| # The circular doubly linked list starts and ends with a sentinel element. |
| # The sentinel element never gets deleted (this simplifies the algorithm). |
| # Each link is stored as a list of length three: [PREV, NEXT, KEY]. |
| |
| def __init__(*args, **kwds): |
| '''Initialize an ordered dictionary. The signature is the same as |
| regular dictionaries, but keyword arguments are not recommended because |
| their insertion order is arbitrary. |
| |
| ''' |
| if not args: |
| raise TypeError("descriptor '__init__' of 'OrderedDict' object " |
| "needs an argument") |
| self = args[0] |
| args = args[1:] |
| if len(args) > 1: |
| raise TypeError('expected at most 1 arguments, got %d' % len(args)) |
| try: |
| self.__root |
| except AttributeError: |
| self.__root = root = [] # sentinel node |
| root[:] = [root, root, None] |
| self.__map = {} |
| self.__update(*args, **kwds) |
| |
| def __setitem__(self, key, value, dict_setitem=dict.__setitem__): |
| 'od.__setitem__(i, y) <==> od[i]=y' |
| # Setting a new item creates a new link at the end of the linked list, |
| # and the inherited dictionary is updated with the new key/value pair. |
| if key not in self: |
| root = self.__root |
| last = root[0] |
| last[1] = root[0] = self.__map[key] = [last, root, key] |
| return dict_setitem(self, key, value) |
| |
| def __delitem__(self, key, dict_delitem=dict.__delitem__): |
| 'od.__delitem__(y) <==> del od[y]' |
| # Deleting an existing item uses self.__map to find the link which gets |
| # removed by updating the links in the predecessor and successor nodes. |
| dict_delitem(self, key) |
| link_prev, link_next, _ = self.__map.pop(key) |
| link_prev[1] = link_next # update link_prev[NEXT] |
| link_next[0] = link_prev # update link_next[PREV] |
| |
| def __iter__(self): |
| 'od.__iter__() <==> iter(od)' |
| # Traverse the linked list in order. |
| root = self.__root |
| curr = root[1] # start at the first node |
| while curr is not root: |
| yield curr[2] # yield the curr[KEY] |
| curr = curr[1] # move to next node |
| |
| def __reversed__(self): |
| 'od.__reversed__() <==> reversed(od)' |
| # Traverse the linked list in reverse order. |
| root = self.__root |
| curr = root[0] # start at the last node |
| while curr is not root: |
| yield curr[2] # yield the curr[KEY] |
| curr = curr[0] # move to previous node |
| |
| def clear(self): |
| 'od.clear() -> None. Remove all items from od.' |
| root = self.__root |
| root[:] = [root, root, None] |
| self.__map.clear() |
| dict.clear(self) |
| |
| # -- the following methods do not depend on the internal structure -- |
| |
| def keys(self): |
| 'od.keys() -> list of keys in od' |
| return list(self) |
| |
| def values(self): |
| 'od.values() -> list of values in od' |
| return [self[key] for key in self] |
| |
| def items(self): |
| 'od.items() -> list of (key, value) pairs in od' |
| return [(key, self[key]) for key in self] |
| |
| def iterkeys(self): |
| 'od.iterkeys() -> an iterator over the keys in od' |
| return iter(self) |
| |
| def itervalues(self): |
| 'od.itervalues -> an iterator over the values in od' |
| for k in self: |
| yield self[k] |
| |
| def iteritems(self): |
| 'od.iteritems -> an iterator over the (key, value) pairs in od' |
| for k in self: |
| yield (k, self[k]) |
| |
| update = MutableMapping.update |
| |
| __update = update # let subclasses override update without breaking __init__ |
| |
| __marker = object() |
| |
| def pop(self, key, default=__marker): |
| '''od.pop(k[,d]) -> v, remove specified key and return the corresponding |
| value. If key is not found, d is returned if given, otherwise KeyError |
| is raised. |
| |
| ''' |
| if key in self: |
| result = self[key] |
| del self[key] |
| return result |
| if default is self.__marker: |
| raise KeyError(key) |
| return default |
| |
| def setdefault(self, key, default=None): |
| 'od.setdefault(k[,d]) -> od.get(k,d), also set od[k]=d if k not in od' |
| if key in self: |
| return self[key] |
| self[key] = default |
| return default |
| |
| def popitem(self, last=True): |
| '''od.popitem() -> (k, v), return and remove a (key, value) pair. |
| Pairs are returned in LIFO order if last is true or FIFO order if false. |
| |
| ''' |
| if not self: |
| raise KeyError('dictionary is empty') |
| key = next(reversed(self) if last else iter(self)) |
| value = self.pop(key) |
| return key, value |
| |
| def __repr__(self, _repr_running={}): |
| 'od.__repr__() <==> repr(od)' |
| call_key = id(self), _get_ident() |
| if call_key in _repr_running: |
| return '...' |
| _repr_running[call_key] = 1 |
| try: |
| if not self: |
| return '%s()' % (self.__class__.__name__,) |
| return '%s(%r)' % (self.__class__.__name__, self.items()) |
| finally: |
| del _repr_running[call_key] |
| |
| def __reduce__(self): |
| 'Return state information for pickling' |
| items = [[k, self[k]] for k in self] |
| inst_dict = vars(self).copy() |
| for k in vars(OrderedDict()): |
| inst_dict.pop(k, None) |
| if inst_dict: |
| return (self.__class__, (items,), inst_dict) |
| return self.__class__, (items,) |
| |
| def copy(self): |
| 'od.copy() -> a shallow copy of od' |
| return self.__class__(self) |
| |
| @classmethod |
| def fromkeys(cls, iterable, value=None): |
| '''OD.fromkeys(S[, v]) -> New ordered dictionary with keys from S. |
| If not specified, the value defaults to None. |
| |
| ''' |
| self = cls() |
| for key in iterable: |
| self[key] = value |
| return self |
| |
| def __eq__(self, other): |
| '''od.__eq__(y) <==> od==y. Comparison to another OD is order-sensitive |
| while comparison to a regular mapping is order-insensitive. |
| |
| ''' |
| if isinstance(other, OrderedDict): |
| return dict.__eq__(self, other) and all(_imap(_eq, self, other)) |
| return dict.__eq__(self, other) |
| |
| def __ne__(self, other): |
| 'od.__ne__(y) <==> od!=y' |
| return not self == other |
| |
| # -- the following methods support python 3.x style dictionary views -- |
| |
| def viewkeys(self): |
| "od.viewkeys() -> a set-like object providing a view on od's keys" |
| return KeysView(self) |
| |
| def viewvalues(self): |
| "od.viewvalues() -> an object providing a view on od's values" |
| return ValuesView(self) |
| |
| def viewitems(self): |
| "od.viewitems() -> a set-like object providing a view on od's items" |
| return ItemsView(self) |
| |
| |
| ################################################################################ |
| ### namedtuple |
| ################################################################################ |
| |
| _class_template = '''\ |
| class {typename}(tuple): |
| '{typename}({arg_list})' |
| |
| __slots__ = () |
| |
| _fields = {field_names!r} |
| |
| def __new__(_cls, {arg_list}): |
| 'Create new instance of {typename}({arg_list})' |
| return _tuple.__new__(_cls, ({arg_list})) |
| |
| @classmethod |
| def _make(cls, iterable, new=tuple.__new__, len=len): |
| 'Make a new {typename} object from a sequence or iterable' |
| result = new(cls, iterable) |
| if len(result) != {num_fields:d}: |
| raise TypeError('Expected {num_fields:d} arguments, got %d' % len(result)) |
| return result |
| |
| def __repr__(self): |
| 'Return a nicely formatted representation string' |
| return '{typename}({repr_fmt})' % self |
| |
| def _asdict(self): |
| 'Return a new OrderedDict which maps field names to their values' |
| return OrderedDict(zip(self._fields, self)) |
| |
| def _replace(_self, **kwds): |
| 'Return a new {typename} object replacing specified fields with new values' |
| result = _self._make(map(kwds.pop, {field_names!r}, _self)) |
| if kwds: |
| raise ValueError('Got unexpected field names: %r' % kwds.keys()) |
| return result |
| |
| def __getnewargs__(self): |
| 'Return self as a plain tuple. Used by copy and pickle.' |
| return tuple(self) |
| |
| __dict__ = _property(_asdict) |
| |
| def __getstate__(self): |
| 'Exclude the OrderedDict from pickling' |
| pass |
| |
| {field_defs} |
| ''' |
| |
| _repr_template = '{name}=%r' |
| |
| _field_template = '''\ |
| {name} = _property(_itemgetter({index:d}), doc='Alias for field number {index:d}') |
| ''' |
| |
| def namedtuple(typename, field_names, verbose=False, rename=False): |
| """Returns a new subclass of tuple with named fields. |
| |
| >>> Point = namedtuple('Point', ['x', 'y']) |
| >>> Point.__doc__ # docstring for the new class |
| 'Point(x, y)' |
| >>> p = Point(11, y=22) # instantiate with positional args or keywords |
| >>> p[0] + p[1] # indexable like a plain tuple |
| 33 |
| >>> x, y = p # unpack like a regular tuple |
| >>> x, y |
| (11, 22) |
| >>> p.x + p.y # fields also accessable by name |
| 33 |
| >>> d = p._asdict() # convert to a dictionary |
| >>> d['x'] |
| 11 |
| >>> Point(**d) # convert from a dictionary |
| Point(x=11, y=22) |
| >>> p._replace(x=100) # _replace() is like str.replace() but targets named fields |
| Point(x=100, y=22) |
| |
| """ |
| |
| # Validate the field names. At the user's option, either generate an error |
| # message or automatically replace the field name with a valid name. |
| if isinstance(field_names, basestring): |
| field_names = field_names.replace(',', ' ').split() |
| field_names = map(str, field_names) |
| typename = str(typename) |
| if rename: |
| seen = set() |
| for index, name in enumerate(field_names): |
| if (not all(c.isalnum() or c=='_' for c in name) |
| or _iskeyword(name) |
| or not name |
| or name[0].isdigit() |
| or name.startswith('_') |
| or name in seen): |
| field_names[index] = '_%d' % index |
| seen.add(name) |
| for name in [typename] + field_names: |
| if type(name) != str: |
| raise TypeError('Type names and field names must be strings') |
| if not all(c.isalnum() or c=='_' for c in name): |
| raise ValueError('Type names and field names can only contain ' |
| 'alphanumeric characters and underscores: %r' % name) |
| if _iskeyword(name): |
| raise ValueError('Type names and field names cannot be a ' |
| 'keyword: %r' % name) |
| if name[0].isdigit(): |
| raise ValueError('Type names and field names cannot start with ' |
| 'a number: %r' % name) |
| seen = set() |
| for name in field_names: |
| if name.startswith('_') and not rename: |
| raise ValueError('Field names cannot start with an underscore: ' |
| '%r' % name) |
| if name in seen: |
| raise ValueError('Encountered duplicate field name: %r' % name) |
| seen.add(name) |
| |
| # Fill-in the class template |
| class_definition = _class_template.format( |
| typename = typename, |
| field_names = tuple(field_names), |
| num_fields = len(field_names), |
| arg_list = repr(tuple(field_names)).replace("'", "")[1:-1], |
| repr_fmt = ', '.join(_repr_template.format(name=name) |
| for name in field_names), |
| field_defs = '\n'.join(_field_template.format(index=index, name=name) |
| for index, name in enumerate(field_names)) |
| ) |
| if verbose: |
| print class_definition |
| |
| # Execute the template string in a temporary namespace and support |
| # tracing utilities by setting a value for frame.f_globals['__name__'] |
| namespace = dict(_itemgetter=_itemgetter, __name__='namedtuple_%s' % typename, |
| OrderedDict=OrderedDict, _property=property, _tuple=tuple) |
| try: |
| exec class_definition in namespace |
| except SyntaxError as e: |
| raise SyntaxError(e.message + ':\n' + class_definition) |
| result = namespace[typename] |
| |
| # For pickling to work, the __module__ variable needs to be set to the frame |
| # where the named tuple is created. Bypass this step in environments where |
| # sys._getframe is not defined (Jython for example) or sys._getframe is not |
| # defined for arguments greater than 0 (IronPython). |
| try: |
| result.__module__ = _sys._getframe(1).f_globals.get('__name__', '__main__') |
| except (AttributeError, ValueError): |
| pass |
| |
| return result |
| |
| |
| ######################################################################## |
| ### Counter |
| ######################################################################## |
| |
| class Counter(dict): |
| '''Dict subclass for counting hashable items. Sometimes called a bag |
| or multiset. Elements are stored as dictionary keys and their counts |
| are stored as dictionary values. |
| |
| >>> c = Counter('abcdeabcdabcaba') # count elements from a string |
| |
| >>> c.most_common(3) # three most common elements |
| [('a', 5), ('b', 4), ('c', 3)] |
| >>> sorted(c) # list all unique elements |
| ['a', 'b', 'c', 'd', 'e'] |
| >>> ''.join(sorted(c.elements())) # list elements with repetitions |
| 'aaaaabbbbcccdde' |
| >>> sum(c.values()) # total of all counts |
| 15 |
| |
| >>> c['a'] # count of letter 'a' |
| 5 |
| >>> for elem in 'shazam': # update counts from an iterable |
| ... c[elem] += 1 # by adding 1 to each element's count |
| >>> c['a'] # now there are seven 'a' |
| 7 |
| >>> del c['b'] # remove all 'b' |
| >>> c['b'] # now there are zero 'b' |
| 0 |
| |
| >>> d = Counter('simsalabim') # make another counter |
| >>> c.update(d) # add in the second counter |
| >>> c['a'] # now there are nine 'a' |
| 9 |
| |
| >>> c.clear() # empty the counter |
| >>> c |
| Counter() |
| |
| Note: If a count is set to zero or reduced to zero, it will remain |
| in the counter until the entry is deleted or the counter is cleared: |
| |
| >>> c = Counter('aaabbc') |
| >>> c['b'] -= 2 # reduce the count of 'b' by two |
| >>> c.most_common() # 'b' is still in, but its count is zero |
| [('a', 3), ('c', 1), ('b', 0)] |
| |
| ''' |
| # References: |
| # http://en.wikipedia.org/wiki/Multiset |
| # http://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html |
| # http://www.demo2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm |
| # http://code.activestate.com/recipes/259174/ |
| # Knuth, TAOCP Vol. II section 4.6.3 |
| |
| def __init__(*args, **kwds): |
| '''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 new, empty counter |
| >>> c = Counter('gallahad') # a new counter from an iterable |
| >>> c = Counter({'a': 4, 'b': 2}) # a new counter from a mapping |
| >>> c = Counter(a=4, b=2) # a new counter from keyword args |
| |
| ''' |
| if not args: |
| raise TypeError("descriptor '__init__' of 'Counter' object " |
| "needs an argument") |
| self = args[0] |
| args = args[1:] |
| if len(args) > 1: |
| raise TypeError('expected at most 1 arguments, got %d' % len(args)) |
| super(Counter, self).__init__() |
| self.update(*args, **kwds) |
| |
| def __missing__(self, key): |
| 'The count of elements not in the Counter is zero.' |
| # Needed so that self[missing_item] does not raise KeyError |
| return 0 |
| |
| def most_common(self, n=None): |
| '''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('abcdeabcdabcaba').most_common(3) |
| [('a', 5), ('b', 4), ('c', 3)] |
| |
| ''' |
| # Emulate Bag.sortedByCount from Smalltalk |
| if n is None: |
| return sorted(self.iteritems(), key=_itemgetter(1), reverse=True) |
| return _heapq.nlargest(n, self.iteritems(), key=_itemgetter(1)) |
| |
| def elements(self): |
| '''Iterator over elements repeating each as many times as its count. |
| |
| >>> c = Counter('ABCABC') |
| >>> sorted(c.elements()) |
| ['A', 'A', 'B', 'B', 'C', 'C'] |
| |
| # Knuth's example for prime factors of 1836: 2**2 * 3**3 * 17**1 |
| >>> prime_factors = Counter({2: 2, 3: 3, 17: 1}) |
| >>> product = 1 |
| >>> for factor in prime_factors.elements(): # loop over factors |
| ... product *= factor # and multiply them |
| >>> product |
| 1836 |
| |
| Note, if an element's count has been set to zero or is a negative |
| number, elements() will ignore it. |
| |
| ''' |
| # Emulate Bag.do from Smalltalk and Multiset.begin from C++. |
| return _chain.from_iterable(_starmap(_repeat, self.iteritems())) |
| |
| # Override dict methods where necessary |
| |
| @classmethod |
| def fromkeys(cls, iterable, v=None): |
| # There is no equivalent method for counters because setting v=1 |
| # means that no element can have a count greater than one. |
| raise NotImplementedError( |
| 'Counter.fromkeys() is undefined. Use Counter(iterable) instead.') |
| |
| def update(*args, **kwds): |
| '''Like dict.update() but add counts instead of replacing them. |
| |
| Source can be an iterable, a dictionary, or another Counter instance. |
| |
| >>> c = Counter('which') |
| >>> c.update('witch') # add elements from another iterable |
| >>> d = Counter('watch') |
| >>> c.update(d) # add elements from another counter |
| >>> c['h'] # four 'h' in which, witch, and watch |
| 4 |
| |
| ''' |
| # The regular dict.update() operation makes no sense here because the |
| # replace behavior results in the some of original untouched counts |
| # being mixed-in with all of the other counts for a mismash that |
| # doesn't have a straight-forward interpretation in most counting |
| # contexts. Instead, we implement straight-addition. Both the inputs |
| # and outputs are allowed to contain zero and negative counts. |
| |
| if not args: |
| raise TypeError("descriptor 'update' of 'Counter' object " |
| "needs an argument") |
| self = args[0] |
| args = args[1:] |
| if len(args) > 1: |
| raise TypeError('expected at most 1 arguments, got %d' % len(args)) |
| iterable = args[0] if args else None |
| if iterable is not None: |
| if isinstance(iterable, Mapping): |
| if self: |
| self_get = self.get |
| for elem, count in iterable.iteritems(): |
| self[elem] = self_get(elem, 0) + count |
| else: |
| super(Counter, self).update(iterable) # fast path when counter is empty |
| else: |
| self_get = self.get |
| for elem in iterable: |
| self[elem] = self_get(elem, 0) + 1 |
| if kwds: |
| self.update(kwds) |
| |
| def subtract(*args, **kwds): |
| '''Like dict.update() but subtracts counts instead of replacing them. |
| Counts can be reduced below zero. Both the inputs and outputs are |
| allowed to contain zero and negative counts. |
| |
| Source can be an iterable, a dictionary, or another Counter instance. |
| |
| >>> c = Counter('which') |
| >>> c.subtract('witch') # subtract elements from another iterable |
| >>> c.subtract(Counter('watch')) # subtract elements from another counter |
| >>> c['h'] # 2 in which, minus 1 in witch, minus 1 in watch |
| 0 |
| >>> c['w'] # 1 in which, minus 1 in witch, minus 1 in watch |
| -1 |
| |
| ''' |
| if not args: |
| raise TypeError("descriptor 'subtract' of 'Counter' object " |
| "needs an argument") |
| self = args[0] |
| args = args[1:] |
| if len(args) > 1: |
| raise TypeError('expected at most 1 arguments, got %d' % len(args)) |
| iterable = args[0] if args else None |
| if iterable is not None: |
| self_get = self.get |
| if isinstance(iterable, Mapping): |
| for elem, count in iterable.items(): |
| self[elem] = self_get(elem, 0) - count |
| else: |
| for elem in iterable: |
| self[elem] = self_get(elem, 0) - 1 |
| if kwds: |
| self.subtract(kwds) |
| |
| def copy(self): |
| 'Return a shallow copy.' |
| return self.__class__(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: |
| super(Counter, self).__delitem__(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) |
| |
| # Multiset-style mathematical operations discussed in: |
| # Knuth TAOCP Volume II section 4.6.3 exercise 19 |
| # and at http://en.wikipedia.org/wiki/Multiset |
| # |
| # Outputs guaranteed to only include positive counts. |
| # |
| # To strip negative and zero counts, add-in an empty counter: |
| # c += Counter() |
| |
| def __add__(self, other): |
| '''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() |
| for elem, count in self.items(): |
| newcount = count + other[elem] |
| if newcount > 0: |
| result[elem] = newcount |
| for elem, count in other.items(): |
| if elem not in self and count > 0: |
| result[elem] = count |
| return result |
| |
| def __sub__(self, other): |
| ''' 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() |
| for elem, count in self.items(): |
| newcount = count - other[elem] |
| if newcount > 0: |
| result[elem] = newcount |
| for elem, count in other.items(): |
| if elem not in self and count < 0: |
| result[elem] = 0 - count |
| return result |
| |
| def __or__(self, other): |
| '''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 |
| result = Counter() |
| for elem, count in self.items(): |
| other_count = other[elem] |
| newcount = other_count if count < other_count else count |
| if newcount > 0: |
| result[elem] = newcount |
| for elem, count in other.items(): |
| if elem not in self and count > 0: |
| result[elem] = count |
| return result |
| |
| def __and__(self, other): |
| ''' Intersection is the minimum of corresponding counts. |
| |
| >>> Counter('abbb') & Counter('bcc') |
| Counter({'b': 1}) |
| |
| ''' |
| if not isinstance(other, Counter): |
| return NotImplemented |
| result = Counter() |
| for elem, count in self.items(): |
| other_count = other[elem] |
| newcount = count if count < other_count else other_count |
| if newcount > 0: |
| result[elem] = newcount |
| return result |
| |
| |
| if __name__ == '__main__': |
| # verify that instances can be pickled |
| from cPickle import loads, dumps |
| Point = namedtuple('Point', 'x, y', True) |
| p = Point(x=10, y=20) |
| assert p == loads(dumps(p)) |
| |
| # test and demonstrate ability to override methods |
| class Point(namedtuple('Point', 'x y')): |
| __slots__ = () |
| @property |
| def hypot(self): |
| return (self.x ** 2 + self.y ** 2) ** 0.5 |
| def __str__(self): |
| return 'Point: x=%6.3f y=%6.3f hypot=%6.3f' % (self.x, self.y, self.hypot) |
| |
| for p in Point(3, 4), Point(14, 5/7.): |
| print p |
| |
| class Point(namedtuple('Point', 'x y')): |
| 'Point class with optimized _make() and _replace() without error-checking' |
| __slots__ = () |
| _make = classmethod(tuple.__new__) |
| def _replace(self, _map=map, **kwds): |
| return self._make(_map(kwds.get, ('x', 'y'), self)) |
| |
| print Point(11, 22)._replace(x=100) |
| |
| Point3D = namedtuple('Point3D', Point._fields + ('z',)) |
| print Point3D.__doc__ |
| |
| import doctest |
| TestResults = namedtuple('TestResults', 'failed attempted') |
| print TestResults(*doctest.testmod()) |