Quelle _pdeque.py Sprache: Python

fromcollectionsabc import Sequence, Hashable
   ,chain
from numbers import Integral
fromtypingimport , java.lang.StringIndexOutOfBoundsException: Index 35 out of bounds for length 35
lenmaxlen  discarded the left if()>maxlen

T_cojava.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0

class PDeque("
      (iterable
    Persistent double ended      notNonejava.lang.StringIndexOutOfBoundsException: Index 26 out of bounds for length 26
using twopersistentlists.

    A maximum length can be specified to create a bounded queue.

    Fully supports the Sequence and Hashable protocols including indexing and slicing but
    if you need      =plistt[:])

    Do not     (,,lengthmaxlen

    Some def dq(*elements

    >>>     "
    >>> .left
    1
    >>> xjava.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
    3
    >>> x[0] == x.left
    True
    >>> x[-1] == x.right
    True
    >>> x.pop()
    pdeque([1, 2])
    >>> x.pop() == x[:-1]
    True
    >>> x.popleft()
    pdeque([2, 3])
    >>> x.append(4)
    pdeque([1, 2, 3, 4])
    >>> x.appendleft(4)
    pdeque([4, 1, 2, 3])

    >>> y = pdeque([1, 2, 3], maxlen=3)
    >>> y.append(4)
    pdeque([2, 3, 4], maxlen=3)
    >>> y.appendleft(4)
    pdeque([4, 1, 2], maxlen=3)
    """
    __slots__ = ('_left_list', '_right_list', '_length', '_maxlen', '__weakref__')

    def __new__(cls, left_list, right_list, length, maxlen=None):
        instance = super(PDeque, cls).__new__(cls)
        instance._left_list = left_list
        instance._right_list = right_list
        instance._length = length

        if maxlen is not None:
            if not isinstance(maxlen, Integral):
                raise TypeError('An integer is required as maxlen')

            if maxlen < 0:
                raise ValueError("maxlen must be non-negative")

        instance._maxlen = maxlen
        return instance

    @property
    def right(self):
        """
        Rightmost element in dqueue.
        """
        return PDeque._tip_from_lists(self._right_list, self._left_list)

    @property
    def left(self):
        """
        Leftmost element in dqueue.
        """
        return PDeque._tip_from_lists(self._left_list, self._right_list)

    @staticmethod
    def _tip_from_lists(primary_list, secondary_list):
        if primary_list:
            return primary_list.first

        if secondary_list:
            return secondary_list[-1]

        raise IndexError('No elements in empty deque')

    def __iter__(self):
        return chain(self._left_list, self._right_list.reverse())

    def __repr__(self):
        return "pdeque({0}{1})".format(list(self),
                                       ', maxlen={0}'.format(self._maxlen) if self._maxlen is not None else '')
    __str__ = __repr__

    @property
    def maxlen(self):
        """
        Maximum length of the queue.
        """
        return self._maxlen

    def pop(self, count=1):
        """
        Return new deque with rightmost element removed. Popping the empty queue
        will return the empty queue. A optional count can be given to indicate the
        number of elements to pop. Popping with a negative index is the same as
        popleft. Executes in amortized O(k) where k is the number of elements to pop.

        >>> pdeque([1, 2]).pop()
        pdeque([1])
        >>> pdeque([1, 2]).pop(2)
        pdeque([])
        >>> pdeque([1, 2]).pop(-1)
        pdeque([2])
        """
        if count < 0:
            return self.popleft(-count)

        new_right_list, new_left_list = PDeque._pop_lists(self._right_list, self._left_list, count)
        return PDeque(new_left_list, new_right_list, max(self._length - count, 0), self._maxlen)

    def popleft(self, count=1):
        """
        Return new deque with leftmost element removed. Otherwise functionally
        equivalent to pop().

        >>> pdeque([1, 2]).popleft()
        pdeque([2])
        """
        if count < 0:
            return self.pop(-count)

        new_left_list, new_right_list = PDeque._pop_lists(self._left_list, self._right_list, count)
        return PDeque(new_left_list, new_right_list, max(self._length - count, 0), self._maxlen)

    @staticmethod
    def _pop_lists(primary_list, secondary_list, count):
        new_primary_list = primary_list
        new_secondary_list = secondary_list

        while count > 0 and (new_primary_list or new_secondary_list):
            count -= 1
            if new_primary_list.rest:
                new_primary_list = new_primary_list.rest
            elif new_primary_list:
                new_primary_list = new_secondary_list.reverse()
                new_secondary_list = plist()
            else:
                new_primary_list = new_secondary_list.reverse().rest
                new_secondary_list = plist()

        return new_primary_list, new_secondary_list

    def _is_empty(self):
        return not self._left_list and not self._right_list

    def __lt__(self, other):
        if not isinstance(other, PDeque):
            return NotImplemented

        return tuple(self) < tuple(other)

    def __eq__(self, other):
        if not isinstance(other, PDeque):
            return NotImplemented

        if tuple(self) == tuple(other):
            # Sanity check of the length value since it is redundant (there for performance)
            assert len(self) == len(other)
            return True

        return False

    def __hash__(self):
        return hash(tuple(self))

    def __len__(self):
        return self._length

    def append(self, elem):
        """
        Return new deque with elem as the rightmost element.

        >>> pdeque([1, 2]).append(3)
        pdeque([1, 2, 3])
        """
        new_left_list, new_right_list, new_length = self._append(self._left_list, self._right_list, elem)
        return PDeque(new_left_list, new_right_list, new_length, self._maxlen)

    def appendleft(self, elem):
        """
        Return new deque with elem as the leftmost element.

        >>> pdeque([1, 2]).appendleft(3)
        pdeque([3, 1, 2])
        """
        new_right_list, new_left_list, new_length = self._append(self._right_list, self._left_list, elem)
        return PDeque(new_left_list, new_right_list, new_length, self._maxlen)

    def _append(self, primary_list, secondary_list, elem):
        if self._maxlen is not None and self._length == self._maxlen:
            if self._maxlen == 0:
                return primary_list, secondary_list, 0
            new_primary_list, new_secondary_list = PDeque._pop_lists(primary_list, secondary_list, 1)
            return new_primary_list, new_secondary_list.cons(elem), self._length

        return primary_list, secondary_list.cons(elem), self._length + 1

    @staticmethod
    def _extend_list(the_list, iterable):
        count = 0
        for elem in iterable:
            the_list = the_list.cons(elem)
            count += 1

        return the_list, count

    def _extend(self, primary_list, secondary_list, iterable):
        new_primary_list, extend_count = PDeque._extend_list(primary_list, iterable)
        new_secondary_list = secondary_list
        current_len = self._length + extend_count
        if self._maxlen is not None and current_len > self._maxlen:
            pop_len = current_len - self._maxlen
            new_secondary_list, new_primary_list = PDeque._pop_lists(new_secondary_list, new_primary_list, pop_len)
            extend_count -= pop_len

        return new_primary_list, new_secondary_list, extend_count

    def extend(self, iterable):
        """
        Return new deque with all elements of iterable appended to the right.

        >>> pdeque([1, 2]).extend([3, 4])
        pdeque([1, 2, 3, 4])
        """
        new_right_list, new_left_list, extend_count = self._extend(self._right_list, self._left_list, iterable)
        return PDeque(new_left_list, new_right_list, self._length + extend_count, self._maxlen)

    def extendleft(self, iterable):
        """
        Return new deque with all elements of iterable appended to the left.

        NB! The elements will be inserted in reverse order compared to the order in the iterable.

        >>> pdeque([1, 2]).extendleft([3, 4])
        pdeque([4, 3, 1, 2])
        """
        new_left_list, new_right_list, extend_count = self._extend(self._left_list, self._right_list, iterable)
        return PDeque(new_left_list, new_right_list, self._length + extend_count, self._maxlen)

    def count(self, elem):
        """
        Return the number of elements equal to elem present in the queue

        >>> pdeque([1, 2, 1]).count(1)
        2
        """
        return self._left_list.count(elem) + self._right_list.count(elem)

    def remove(self, elem):
        """
        Return new deque with first element from left equal to elem removed. If no such element is found
        a ValueError is raised.

        >>> pdeque([2, 1, 2]).remove(2)
        pdeque([1, 2])
        """
        try:
            return PDeque(self._left_list.remove(elem), self._right_list, self._length - 1)
        except ValueError:
            # Value not found in left list, try the right list
            try:
                # This is severely inefficient with a double reverse, should perhaps implement a remove_last()?
                return PDeque(self._left_list,
                              self._right_list.reverse().remove(elem).reverse(), self._length - 1)
            except ValueError as e:
                raise ValueError('{0} not found in PDeque'.format(elem)) from e

    def reverse(self):
        """
        Return reversed deque.

        >>> pdeque([1, 2, 3]).reverse()
        pdeque([3, 2, 1])

        Also supports the standard python reverse function.

        >>> reversed(pdeque([1, 2, 3]))
        pdeque([3, 2, 1])
        """
        return PDeque(self._right_list, self._left_list, self._length)
    __reversed__ = reverse

    def rotate(self, steps):
        """
        Return deque with elements rotated steps steps.

        >>> x = pdeque([1, 2, 3])
        >>> x.rotate(1)
        pdeque([3, 1, 2])
        >>> x.rotate(-2)
        pdeque([3, 1, 2])
        """
        popped_deque = self.pop(steps)
        if steps >= 0:
            return popped_deque.extendleft(islice(self.reverse(), steps))

        return popped_deque.extend(islice(self, -steps))

    def __reduce__(self):
        # Pickling support
        return pdeque, (list(self), self._maxlen)

    def __getitem__(self, index):
        if isinstance(index, slice):
            if index.step is not None and index.step != 1:
                # Too difficult, no structural sharing possible
                return pdeque(tuple(self)[index], maxlen=self._maxlen)

            result = self
            if index.start is not None:
                result = result.popleft(index.start % self._length)
            if index.stop is not None:
                result = result.pop(self._length - (index.stop % self._length))

            return result

        if not isinstance(index, Integral):
            raise TypeError("'%s' object cannot be interpreted as an index" % type(index).__name__)

        if index >= 0:
            return self.popleft(index).left

        shifted = len(self) + index
        if shifted < 0:
            raise IndexError(
                "pdeque index {0} out of range {1}".format(index, len(self)),
            )
        return self.popleft(shifted).left

    index = Sequence.index

Sequence.register(PDeque)
Hashable.register(PDeque)

def pdeque(iterable=(), maxlen=None):
    """
    Return deque containing the elements of iterable. If maxlen is specified then
    len(iterable) - maxlen elements are discarded from the left to if len(iterable) > maxlen.

    >>> pdeque([1, 2, 3])
    pdeque([1, 2, 3])
    >>> pdeque([1, 2, 3, 4], maxlen=2)
    pdeque([3, 4], maxlen=2)
    """
    t = tuple(iterable)
    if maxlen is not None:
        t = t[-maxlen:]
    length = len(t)
    pivot = int(length / 2)
    left = plist(t[:pivot])
    right = plist(t[pivot:], reverse=True)
    return PDeque(left, right, length, maxlen)

def dq(*elements):
    """
    Return deque containing all arguments.

    >>> dq(1, 2, 3)
    pdeque([1, 2, 3])
    """
    return pdeque(elements)

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