numpy.rollaxis()函数| Python

numpy.rollaxis()函数向后滚动指定的轴，直到它位于给定位置。

Syntax : numpy.rollaxis(arr, axis, start=0)
Parameters :
arr : [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.
Return : [ndarray] In earlier NumPy versions, arr is returned only if the order of the axes is changed, otherwise the input array is returned. For NumPy >= 1.10.0, a view of arr is always returned.

代码#1：

# Python program explaining
# numpy.rollaxis() function
  
# importing numpy as geek 
import numpy as geek
  
arr = geek.ones((1, 2, 3, 4))
  
gfg = geek.rollaxis(arr, 3, 1).shape
  
print (gfg)

输出 ：

(1, 4, 2, 3)

代码#2：

# Python program explaining
# numpy.rollaxis() function
  
# importing numpy as geek 
import numpy as geek
  
arr = geek.ones((1, 2, 3, 4))
  
gfg = geek.rollaxis(arr, 2).shape
  
print (gfg)

输出 ：

(3, 1, 2, 4)