计算 NumPy 数组的对角线元素之和

有时我们需要求右上、左上、右下或左下对角元素的总和。 Numpy 为我们提供了使用 numpy.trace() 和numpy.diagonal()方法计算不同对角线元素之和的工具。

方法一：使用numpy.trace()求对角线元素之和

Syntax : numpy.trace(a, offset=0, axis1=0, axis2=1, dtype=None, out=None)  

示例 1：对于3X3 Numpy 矩阵

Python3

# importing Numpy package
import numpy as np
  
# creating a 3X3 Numpy matrix
n_array = np.array([[55, 25, 15],
                    [30, 44, 2],
                    [11, 45, 77]])
  
# Displaying the Matrix
print("Numpy Matrix is:")
print(n_array)
  
# calculating the Trace of a matrix
trace = np.trace(n_array)
  
  
print("\nTrace of given 3X3 matrix:")
print(trace)

输出：

示例 2：对于4X4 Numpy 矩阵

Python3

# importing Numpy package
import numpy as np
  
# creating a 4X4 Numpy matrix
n_array = np.array([[55, 25, 15, 41],
                    [30, 44, 2, 54],
                    [11, 45, 77, 11],
                    [11, 212, 4, 20]])
  
# Displaying the Matrix
print("Numpy Matrix is:")
print(n_array)
  
# calculating the Trace of a matrix
trace = np.trace(n_array)
  
  
print("\nTrace of given 4X4 matrix:")
print(trace)

输出：

方法 2：使用numpy.diagonal()求对角线元素的总和

句法 ：

numpy.diagonal(a, offset=0, axis1=0, axis2=1

示例 1：对于3X3 Numpy 矩阵

Python3

# importing Numpy package
import numpy as np
  
# creating a 3X3 Numpy matrix
n_array = np.array([[55, 25, 15],
                    [30, 44, 2],
                    [11, 45, 77]])
  
# Displaying the Matrix
print("Numpy Matrix is:")
print(n_array)
  
# Finding the diagonal elements of a matrix
diag = np.diagonal(n_array)
  
print("\nDiagonal elements are:")
print(diag)
  
print("\nSum of Diagonal elements is:")
print(sum(diag))

输出：

示例 2：对于5X5 Numpy 矩阵

Python3

# importing Numpy package
import numpy as np
  
# creating a 5X5 Numpy matrix
n_array = np.array([[5, 2, 1, 4, 6],
                    [9, 4, 2, 5, 2],
                    [11, 5, 7, 3, 9],
                    [5, 6, 6, 7, 2],
                    [7, 5, 9, 3, 3]])
  
# Displaying the Matrix
print("Numpy Matrix is:")
print(n_array)
  
# Finding the diagonal elements of a matrix
diag = np.diagonal(n_array)
  
print("\nDiagonal elements are:")
print(diag)
  
print("\nSum of Diagonal elements is:")
print(sum(diag))

输出：