dask.array.roll

dask.array.roll¶

dask.array.roll(array, shift, axis=None)[source]¶

Roll array elements along a given axis.

This docstring was copied from numpy.roll.

Some inconsistencies with the Dask version may exist.

Elements that roll beyond the last position are re-introduced at the first.

Parameters

aarray_like (Not supported in Dask): Input array.
shiftint or tuple of ints: The number of places by which elements are shifted. If a tuple, then axis must be a tuple of the same size, and each of the given axes is shifted by the corresponding number. If an int while axis is a tuple of ints, then the same value is used for all given axes.
axisint or tuple of ints, optional: Axis or axes along which elements are shifted. By default, the array is flattened before shifting, after which the original shape is restored.

Returns

resndarray: Output array, with the same shape as a.

See also

rollaxis: Roll the specified axis backwards, until it lies in a given position.

Notes

New in version 1.12.0.

Supports rolling over multiple dimensions simultaneously.

Examples

>>> x = np.arange(10)  
>>> np.roll(x, 2)  
array([8, 9, 0, 1, 2, 3, 4, 5, 6, 7])
>>> np.roll(x, -2)  
array([2, 3, 4, 5, 6, 7, 8, 9, 0, 1])

>>> x2 = np.reshape(x, (2, 5))  
>>> x2  
array([[0, 1, 2, 3, 4],
       [5, 6, 7, 8, 9]])
>>> np.roll(x2, 1)  
array([[9, 0, 1, 2, 3],
       [4, 5, 6, 7, 8]])
>>> np.roll(x2, -1)  
array([[1, 2, 3, 4, 5],
       [6, 7, 8, 9, 0]])
>>> np.roll(x2, 1, axis=0)  
array([[5, 6, 7, 8, 9],
       [0, 1, 2, 3, 4]])
>>> np.roll(x2, -1, axis=0)  
array([[5, 6, 7, 8, 9],
       [0, 1, 2, 3, 4]])
>>> np.roll(x2, 1, axis=1)  
array([[4, 0, 1, 2, 3],
       [9, 5, 6, 7, 8]])
>>> np.roll(x2, -1, axis=1)  
array([[1, 2, 3, 4, 0],
       [6, 7, 8, 9, 5]])
>>> np.roll(x2, (1, 1), axis=(1, 0))  
array([[9, 5, 6, 7, 8],
       [4, 0, 1, 2, 3]])
>>> np.roll(x2, (2, 1), axis=(1, 0))  
array([[8, 9, 5, 6, 7],
       [3, 4, 0, 1, 2]])

dask.array.rint

dask.array.rollaxis