Python OrderedDict.popitem方法代码示例

# 需要导入模块: from cyordereddict import OrderedDict [as 别名]
# 或者: from cyordereddict.OrderedDict import popitem [as 别名]
 def test_popitem(self):
     pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
     shuffle(pairs)
     od = OrderedDict(pairs)
     while pairs:
         self.assertEqual(od.popitem(), pairs.pop())
     with self.assertRaises(KeyError):
         od.popitem()
     self.assertEqual(len(od), 0)

# 需要导入模块: from cyordereddict import OrderedDict [as 别名]
# 或者: from cyordereddict.OrderedDict import popitem [as 别名]
class OrderedSet(collections.MutableSet, collections.Sequence):
    """
    An OrderedSet is a custom MutableSet that remembers its order, so that
    every entry has an index that can be looked up.

    Based on version written by Luminoso Technologies:
        https://github.com/LuminosoInsight/ordered-set

    Unlike that implementation, this class uses OrderedDict as storage
    and supports key removal. We drop support for indexing, and add support
    for fixed-size sets with maxlen parameter.

    With a small modification, this class can be made into an LRU cache.
    """
    def __init__(self, iterable=None, maxlen=None):
        self._mapping = OrderedDict()
        self._maxlen = maxlen
        if iterable is not None:
            self |= iterable

    def __len__(self):
        return len(self._mapping)

    def __getitem__(self, index):
        """
        Get the item at a given index.

        If `index` is a slice, you will get back that slice of items. If it's
        the slice [:], exactly the same object is returned. (If you want an
        independent copy of an OrderedSet, use `OrderedSet.copy()`.)

        If `index` is an iterable, you'll get the OrderedSet of items
        corresponding to those indices. This is similar to NumPy's
        "fancy indexing".
        """
        if index == SLICE_ALL:
            return self
        elif hasattr(index, '__index__') or isinstance(index, slice):
            result = self._mapping.keys()[index]
            if isinstance(result, list):
                return OrderedSet(result)
            else:
                return result
        elif isiterable(index):
            keys = self._mapping.keys()
            return OrderedSet([keys[i] for i in index])
        else:
            raise TypeError("Don't know how to index an OrderedSet by %r" % index)

    def copy(self):
        return OrderedSet(self)

    def __getstate__(self):
        if len(self) == 0:
            # The state can't be an empty list.
            # We need to return a truthy value, or else __setstate__ won't be run.
            #
            # This could have been done more gracefully by always putting the state
            # in a tuple, but this way is backwards- and forwards- compatible with
            # previous versions of OrderedSet.
            return (None,)
        else:
            return list(self)

    def __setstate__(self, state):
        if state == (None,):
            self.__init__([])
        else:
            self.__init__(state)

    def __contains__(self, key):
        return key in self._mapping

    def add(self, key):
        """
        Add `key` as an item to this OrderedSet, then return its index.

        If `key` is already in the OrderedSet, return the index it already
        had.
        """
        if key not in self._mapping:
            if self._maxlen is None or len(self._mapping) < self._maxlen:
                self._mapping[key] = 1
            else:
                self._mapping.popitem(last=False)
                self._mapping[key] = 1

    append = add

    def discard(self, key):
        del self._mapping[key]

    def __iter__(self):
        return self._mapping.iterkeys()

    def __reversed__(self):
        return reversed(self._mapping.keys())

    def __repr__(self):
        if not self:
#.........这里部分代码省略.........