77 lines
1.8 KiB
Python
77 lines
1.8 KiB
Python
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from math import inf
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class LazyList(list):
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def __init__(self, iterable):
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self._iter = iterable
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self._length = inf
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self._n = 0
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def __setitem__(self, index, item):
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self._requireLen(index)
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super().__setitem__(index, item)
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def __len__(self):
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return self._length
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def __repr__(self):
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if super().__len__() == 0:
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return '[...]'
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l = []
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for i in range(super().__len__()):
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l.append(str(self[i]))
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if self._length != inf:
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return '[' + ', '.join(l) + ']'
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else:
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return '[' + ', '.join(l) + ', ...]'
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def __str__(self):
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return repr(self)
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def _requireLen(self, length):
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if length==-1:
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num = inf
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else:
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num = length - super().__len__() + 1
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if num > 0:
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i = 0
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while i < num:
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try:
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super().append(self._iter.__next__())
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except StopIteration as e:
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self._length = super().__len__()
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if length!=-1:
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raise e
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return
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i+=1
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def __iter__(self):
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self._n = 0
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return self
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def __next__(self):
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ret = self[self._n]
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self._n += 1
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return ret
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def peak(self, offset=0):
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return self[self._n - 1 + offset]
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def iterIndex(self):
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return self._n - 1
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def __getitem__(self, index):
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self._requireLen(index)
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return super().__getitem__(index)
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def insert(self, index, item):
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self._requireLen(index-1)
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super().insert(index, item)
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def append(self, item):
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self._requireLen(-1)
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super().append(item)
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def extend(self, other):
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self._requireLen(-1)
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super().extend(other)
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