NumPy 数组操作 numpy.rollaxis
此函数将指定的轴向后滚动,直到它位于指定的位置。该函数有三个参数。
numpy.rollaxis(arr, axis, start)
在这里,
序号 | 参数和说明 |
---|---|
1 | arr 输入数组 |
2 | axis 要向后滚动的轴。其他轴的位置相对于彼此不变 |
3 | start 默认为零,导致完全滚动。滚动直到达到指定的位置 |
示例
# It creates 3 dimensional ndarray
import numpy as np
a = np.arange(8).reshape(2,2,2)
print 'The original array:'
print a
print '\n'
# to roll axis-2 to axis-0 (along width to along depth)
print 'After applying rollaxis function:'
print np.rollaxis(a,2)
# to roll axis 0 to 1 (along width to height)
print '\n'
print 'After applying rollaxis function:'
print np.rollaxis(a,2,1)
它的输出如下:
The original array:
[[[0 1]
[2 3]]
[[4 5]
[6 7]]]
After applying rollaxis function:
[[[0 2]
[4 6]]
[[1 3]
[5 7]]]
After applying rollaxis function:
[[[0 2]
[1 3]]
[[4 6]
[5 7]]]