tf.transpose函数的用法讲解（多维情况，看似复杂，其实也简单）

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本文深入解析TensorFlow中tf.transpose函数的使用，通过实例演示不同维度张量的转置操作，适用于2D及更高维度的数据处理。

tf.transpose函数中文意思是转置，对于低维度的转置问题，很简单，不想讨论，直接转置就好（大家看下面文档，一看就懂）。

tf.transpose(a, perm=None, name='transpose')
Transposes a. Permutes the dimensions according to perm.
The returned tensor's dimension i will correspond to the input dimension perm[i]. If perm is not given, it is set to (n-1...0), where n is the rank of the input tensor. Hence by default, this operation performs a regular matrix transpose on 2-D input Tensors.
For example:
# 'x' is [[1 2 3]
# [4 5 6]]
tf.transpose(x) ==> [[1 4]
[2 5]
[3 6]]
# Equivalently
tf.transpose(x perm=[1, 0]) ==> [[1 4]
[2 5]
[3 6]]
# 'perm' is more useful for n-dimensional tensors, for n > 2
# 'x' is [[[1 2 3]
# [4 5 6]]
# [[7 8 9]
# [10 11 12]]]
# Take the transpose of the matrices in dimension-0
tf.transpose(b, perm=[0, 2, 1]) ==> [[[1 4]
[2 5]
[3 6]]
[[7 10]
[8 11]
[9 12]]]
Args:
•a: A Tensor.
•perm: A permutation of the dimensions of a.
•name: A name for the operation (optional).
Returns:
A transposed Tensor.

本文主要讨论高维度的情况：

为了形象理解高维情况，这里以矩阵组合举例：

先定义下： 2 x （3*4）表示2个3*4的矩阵，（其实，它是个3维张量）。

x = [[[1,2,3,4],[5,6,7,8],[9,10,11,12]],[[21,22,23,24],[25,26,27,28],[29,30,31,32]]]

输出：

---------------
[[[ 1 2 3 4]
[ 5 6 7 8]
[ 9 10 11 12]]

[[21 22 23 24]
[25 26 27 28]
[29 30 31 32]]]
---------------

重点来了：

tf.transpose的第二个参数perm=[0,1,2],0代表三维数组的高（即为二维数组的个数），1代表二维数组的行，2代表二维数组的列。
tf.transpose(x, perm=[1,0,2])代表将三位数组的高和行进行转置。

我们写个测试程序如下：

import tensorflow as tf
#x = tf.constant([[1, 2 ,3],[4, 5, 6]])
x = [[[1,2,3,4],[5,6,7,8],[9,10,11,12]],[[21,22,23,24],[25,26,27,28],[29,30,31,32]]]
#a=tf.constant(x)
a=tf.transpose(x, [0, 1, 2])
b=tf.transpose(x, [0, 2, 1])
c=tf.transpose(x, [1, 0, 2])
d=tf.transpose(x, [1, 2, 0])
e=tf.transpose(x, [2, 1, 0])
f=tf.transpose(x, [2, 0, 1])
# 'perm' is more useful for n-dimensional tensors, for n > 2
# 'x' is [[[1 2 3]
# [4 5 6]]
# [[7 8 9]
# [10 11 12]]]
# Take the transpose of the matrices in dimension-0
#tf.transpose(b, perm=[0, 2, 1])
with tf.Session() as sess:
print ('---------------')
print (sess.run(a))
print ('---------------')
print (sess.run(b))
print ('---------------')
print (sess.run(c))
print ('---------------')
print (sess.run(d))
print ('---------------')
print (sess.run(e))
print ('---------------')
print (sess.run(f))
print ('---------------')