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43 lines
1020 B
Python
43 lines
1020 B
Python
from collections import UserDict, UserList
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__all__ = ["LazyDict", "LazyList"]
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class LazyDict(UserDict):
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def __init__(self, data):
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super().__init__()
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self.data = data
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def __getitem__(self, k):
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v = self.data[k]
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if callable(v):
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v = v(k)
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self.data[k] = v
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return v
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class LazyList(UserList):
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def __getitem__(self, k):
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if isinstance(k, slice):
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indices = range(*k.indices(len(self)))
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return [self[i] for i in indices]
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v = self.data[k]
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if callable(v):
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v = v(k)
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self.data[k] = v
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return v
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def __add__(self, other):
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if isinstance(other, LazyList):
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other = list(other)
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elif isinstance(other, list):
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pass
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else:
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return NotImplemented
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return list(self) + other
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def __radd__(self, other):
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if not isinstance(other, list):
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return NotImplemented
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return other + list(self)
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