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# numpy.rollaxis

`numpy.``rollaxis`(a, axis, start=0)

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

  Parameters : | a : ndarray Input array. axis : int The axis to roll backwards. The positions of the other axes do not change relative to one another. start : int, optional The axis is rolled until it lies before this position. The default, 0, results in a “complete” roll.
  Returns : | res : ndarray Output array.

  See also

  `roll`
    Roll the elements of an array by a number of positions along a given axis.

  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)