numpy.rollaxis¶

numpy.
rollaxis
(a, axis, start=0)[source]¶ Roll the specified axis backwards, until it lies in a given position.
This function continues to be supported for backward compatibility, but you should prefer
moveaxis
. Themoveaxis
function was added in NumPy 1.11. Parameters
 andarray
Input array.
 axisint
The axis to be rolled. The positions of the other axes do not change relative to one another.
 startint, optional
When
start <= axis
, the axis is rolled back until it lies in this position. Whenstart > axis
, the axis is rolled until it lies before this position. The default, 0, results in a “complete” roll. The following table describes how negative values ofstart
are interpreted:start
Normalized
start
(arr.ndim+1)
raise
AxisError
arr.ndim
0
⋮
⋮
1
arr.ndim1
0
0
⋮
⋮
arr.ndim
arr.ndim
arr.ndim + 1
raise
AxisError
 Returns
 resndarray
For NumPy >= 1.10.0 a view of a is always returned. For earlier NumPy versions a view of a is returned only if the order of the axes is changed, otherwise the input array is returned.
See also
Examples
>>> a = np.ones((3,4,5,6)) >>> np.rollaxis(a, 3, 1).shape (3, 6, 4, 5) >>> np.rollaxis(a, 2).shape (5, 3, 4, 6) >>> np.rollaxis(a, 1, 4).shape (3, 5, 6, 4)