A pure-python implementation of xrange. Can handle float/long start/stop/step arguments and slice indexing
| 1 | class xrange(object): |
| 2 | """A pure-python implementation of xrange. |
| 3 | |
| 4 | Can handle float/long start/stop/step arguments and slice indexing""" |
| 5 | |
| 6 | __slots__ = ['_slice'] |
| 7 | def __init__(self, *args): |
| 8 | self._slice = slice(*args) |
| 9 | if self._slice.stop is None: |
| 10 | # slice(*args) will never put None in stop unless it was |
| 11 | # given as None explicitly. |
| 12 | raise TypeError("xrange stop must not be None") |
| 13 | |
| 14 | @property |
| 15 | def start(self): |
| 16 | if self._slice.start is not None: |
| 17 | return self._slice.start |
| 18 | return 0 |
| 19 | @property |
| 20 | def stop(self): |
| 21 | return self._slice.stop |
| 22 | @property |
| 23 | def step(self): |
| 24 | if self._slice.step is not None: |
| 25 | return self._slice.step |
| 26 | return 1 |
| 27 | |
| 28 | def __hash__(self): |
| 29 | return hash(self._slice) |
| 30 | |
| 31 | def __cmp__(self, other): |
| 32 | return (cmp(type(self), type(other)) or |
| 33 | cmp(self._slice, other._slice)) |
| 34 | |
| 35 | def __repr__(self): |
| 36 | return '%s(%r, %r, %r)' % (self.__class__.__name__, |
| 37 | self.start, self.stop, self.step) |
| 38 | |
| 39 | def __len__(self): |
| 40 | return self._len() |
| 41 | |
| 42 | def _len(self): |
| 43 | return max(0, int((self.stop - self.start) / self.step)) |
| 44 | |
| 45 | def __getitem__(self, index): |
| 46 | if isinstance(index, slice): |
| 47 | start, stop, step = index.indices(self._len()) |
| 48 | return xrange(self._index(start), |
| 49 | self._index(stop), step*self.step) |
| 50 | elif isinstance(index, (int, long)): |
| 51 | if index < 0: |
| 52 | fixed_index = index + self._len() |
| 53 | else: |
| 54 | fixed_index = index |
| 55 | |
| 56 | if not 0 <= fixed_index < self._len(): |
| 57 | raise IndexError("Index %d out of %r" % (index, self)) |
| 58 | |
| 59 | return self._index(fixed_index) |
| 60 | else: |
no outgoing calls