如何交换一个给定的NumPy数组的列

在这篇文章中，让我们来讨论如何交换一个给定的NumPy数组的列。

步骤:

• 导入NumPy模块
• 创建一个NumPy数组
• 用索引交换列
• 打印最终数组

例子1：交换数组的列。

# importing Module
import numpy as np
 
 
# creating array with shape(4,3)
my_array = np.arange(12).reshape(4, 3)
print("Original array:")
print(my_array)
 
# swapping the column with index of
# original array
my_array[:, [2, 0]] = my_array[:, [0, 2]]
print("After swapping arrays the last column and first column:")
print(my_array)

输出 :

Original array:
[[ 0  1  2]
 [ 3  4  5]
 [ 6  7  8]
 [ 9 10 11]]
After swapping arrays the last column and first column:
[[ 2  1  0]
 [ 5  4  3]
 [ 8  7  6]
 [11 10  9]]

例子2：用用户选择的数组的列来交换。

# Importing Module
import numpy as np
 
 
# Creating array
my_array = np.arange(12).reshape(4, 3)
print("Original Array : ")
print(my_array)
# creating function for swap
 
def Swap(arr, start_index, last_index):
    arr[:, [start_index, last_index]] = arr[:, [last_index, start_index]]
 
# passing parameter into the function
Swap(my_array, 0, 1)
print(" After Swapping :")
print(my_array)

输出 :

Original Array : 
[[ 0  1  2]
 [ 3  4  5]
 [ 6  7  8]
 [ 9 10 11]]
 After Swapping :
[[ 1  0  2]
 [ 4  3  5]
 [ 7  6  8]
 [10  9 11]]