An array-like interface to the blocks of an array. ``BlockView`` provides an array-like interface to the blocks of a dask array. Numpy-style indexing of a ``BlockView`` returns a selection of blocks as a new dask array. You can index ``BlockView`` like a numpy array of shape
| 6167 | |
| 6168 | |
| 6169 | class BlockView: |
| 6170 | """An array-like interface to the blocks of an array. |
| 6171 | |
| 6172 | ``BlockView`` provides an array-like interface |
| 6173 | to the blocks of a dask array. Numpy-style indexing of a |
| 6174 | ``BlockView`` returns a selection of blocks as a new dask array. |
| 6175 | |
| 6176 | You can index ``BlockView`` like a numpy array of shape |
| 6177 | equal to the number of blocks in each dimension, (available as |
| 6178 | array.blocks.size). The dimensionality of the output array matches |
| 6179 | the dimension of this array, even if integer indices are passed. |
| 6180 | Slicing with ``np.newaxis`` or multiple lists is not supported. |
| 6181 | |
| 6182 | Examples |
| 6183 | -------- |
| 6184 | >>> import dask.array as da |
| 6185 | >>> from dask.array.core import BlockView |
| 6186 | >>> x = da.arange(8, chunks=2) |
| 6187 | >>> bv = BlockView(x) |
| 6188 | >>> bv.shape # aliases x.numblocks |
| 6189 | (4,) |
| 6190 | >>> bv.size |
| 6191 | 4 |
| 6192 | >>> bv[0].compute() |
| 6193 | array([0, 1]) |
| 6194 | >>> bv[:3].compute() |
| 6195 | array([0, 1, 2, 3, 4, 5]) |
| 6196 | >>> bv[::2].compute() |
| 6197 | array([0, 1, 4, 5]) |
| 6198 | >>> bv[[-1, 0]].compute() |
| 6199 | array([6, 7, 0, 1]) |
| 6200 | >>> bv.ravel() # doctest: +NORMALIZE_WHITESPACE |
| 6201 | [dask.array<blocks, shape=(2,), dtype=int64, chunksize=(2,), chunktype=numpy.ndarray>, |
| 6202 | dask.array<blocks, shape=(2,), dtype=int64, chunksize=(2,), chunktype=numpy.ndarray>, |
| 6203 | dask.array<blocks, shape=(2,), dtype=int64, chunksize=(2,), chunktype=numpy.ndarray>, |
| 6204 | dask.array<blocks, shape=(2,), dtype=int64, chunksize=(2,), chunktype=numpy.ndarray>] |
| 6205 | |
| 6206 | Returns |
| 6207 | ------- |
| 6208 | An instance of ``da.array.Blockview`` |
| 6209 | """ |
| 6210 | |
| 6211 | def __init__(self, array: Array): |
| 6212 | self._array = array |
| 6213 | |
| 6214 | def __getitem__(self, index: Any) -> Array: |
| 6215 | from dask.array.slicing import normalize_index |
| 6216 | |
| 6217 | if not isinstance(index, tuple): |
| 6218 | index = (index,) |
| 6219 | if sum(isinstance(ind, (np.ndarray, list)) for ind in index) > 1: |
| 6220 | raise ValueError("Can only slice with a single list") |
| 6221 | if any(ind is None for ind in index): |
| 6222 | raise ValueError("Slicing with np.newaxis or None is not supported") |
| 6223 | index = normalize_index(index, self._array.numblocks) |
| 6224 | index = tuple( |
| 6225 | slice(k, k + 1) if isinstance(k, Number) else k # type: ignore[operator] |
| 6226 | for k in index |
no outgoing calls