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@Cartman0
Last active March 5, 2023 12:46
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python Circular List
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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()])
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