python Circular List

CircularList.ipynb

CircularList_deque.py

from collections import deque
'''
This one is implemented in C code for CPython, and the collections python module just imports that name.
https://stackoverflow.com/questions/54526226/how-can-i-see-the-source-code-of-deque-module-from-pythons-collections-library
'''
class Deque_withHead(deque):
    """
    add head
    """
    def __init__(self, iterable=[], maxlen=None):
        super().__init__(iterable=iterable, maxlen=maxlen)
        self._head = 0
        
    def rotate(self, n:int = 1):
        super().rotate(n)
        self._head += n
        if self._head < 0:
            self._head += len(self)
    
    def reverse(self):
        super().reverse()
        self._head = len(self) - 1 - self._head
    
    def head(self)->int:
        return self._head
    
    def reset_head(self):
        pass
    
    def insert(self, i, x):
        super().insert(i, x)
        if i <= self._head:
            self._head += 1
    
    def popleft(self):
        super().popleft()
        self._head -= 1
        if self._head < 0:
            self._head = 0
    
    def pop(self):
        super().pop()
        if self._head > len(self) - 1:
            self._head = len(self) - 1
    
    def iteratornize(self):
        """
        iteratornize_deque(('ABC', 'D', 'EF')) --> ABC D EF
        """
        while self:
            try:
                yield self[0]
                self.rotate(-1)
            except StopIteration:
                break

        
dh=Deque_withHead(['a', 'b', 'c'])
print(dh, dh[dh.head()])