Python Numpy Transpose()

  1. Syntax of numpy.transpose():
  2. Return
  3. Example Codes: numpy.transpose() Method
  4. Example Codes: Set axes Parameter in numpy.transpose() Method

Python Numpy numpy.transpose() reverses the axes of the input array or simply transposes the input array.

Syntax of numpy.transpose():

numpy.transpose(ar, 
                axes=None)

Parameters

ar Array or Object which could be converted into an array.
axis Tuple or list of ints. It specifies the order of axes after permutation.

Return

It returns transpose of the input array if it is a 2-D, however, the input array remains unchanged if it is 1-D.

Example Codes: numpy.transpose() Method

import numpy as np

x=np.array([[2,3,3],
            [3,2,1]])

print("Matrix x:")
print(x)

x_transpose=np.transpose(x)
print("\nTranspose of Matrix x:")
print(x_transpose)

Output:

Matrix x:
[[2 3 3]
 [3 2 1]]

Transpose of Matrix x:
[[2 3]
 [3 2]
 [3 1]]

It returns the transposed version of the input array x. The rows of matrix x become columns of matrix x_transpose and columns of matrix x become rows of matrix x_transpose.

However, if we pass a 1-D array in the numpy.transpose() method, there is no change in the returned array.

import numpy as np

x=np.array([2,3,3])

print("Matrix x:")
print(x)

x_transpose=np.transpose(x)
print("\nTranspose of Matrix x:")
print(x_transpose)

Output:

Matrix x:
[2 3 3]

Transpose of Matrix x:
[2 3 3]

It shows 1-D array remains unchanged after passing through the np.transpose() method.

Example Codes: Set axes Parameter in numpy.transpose() Method

import numpy as np

x = np.random.random((1, 2, 3, 5))

print("Shape of x:")
print(x.shape)

x_permuted=np.transpose(x, (3, 0, 2,1))

print("\nShape of x_permuted:")
print(x_permuted.shape)

Output:

Shape of x:
(1, 2, 3, 5)

Shape of x_permuted:
(5, 1, 3, 2)

Here, axes is passed as second parameter to the numpy.transpose() method.

The ith axis of the returned array will be axes[i]th axis of the input array.

Hence 0th axis in the above example of x becomes 1st axis of x_permuted.

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