基本运算

第一列函数等价于运算符

# -*- coding:utf-8 -*-
import numpy as np


arr1 = np.array([4,6])
arr2 = np.array([2,4])
print('arr1:',arr1)
print('arr2:',arr2)
print("加:")
print("arr1+arr2: " ,arr1+arr2)
print("add函数:" , np.add(arr1,arr2))

print("减:")
print("arr1-arr2: " ,arr1-arr2)
print("subtract函数:" , np.subtract(arr1,arr2))

print("乘:")
print("arr1*arr2: " ,arr1*arr2)
print("multiply函数:" , np.multiply(arr1,arr2))

print("除:")
print("arr1/arr2: " ,arr1/arr2)
print("divide 函数:" , np.divide(arr1,arr2))

print("求余:")
print("arr1%arr2: " ,arr1%arr2)
print("mod 函数:" , np.mod(arr1,arr2))

print("求幂:")
print("arr1**arr2: " ,arr1**arr2)
print("power 函数:" , np.power(arr1,arr2))

比较运算

# -*- coding:utf-8 -*-
import numpy as np

#一维数组的比较
arr1 = np.array([4,6])
arr2 = np.array([2,4])
print('arr1:',arr1)
print('arr2:',arr2)
print('一维数组的比较')
print("arr1>arr2: " ,arr1>arr2)
print("arr1<arr2: " ,arr1<arr2)

#二维数组的比较
arr1 = np.array([[4,6],[8,9]])
arr2 = np.array([[2,4],[7,10]])
print('arr1:',arr1)
print('arr2:',arr2)
print('二维数组的比较')
print("arr1>arr2:\n " ,arr1>arr2)
print("arr1<arr2: \n" ,arr1<arr2)

标量运算

• 向量是一组数，标量是一个数
• 数组的标量运算：将一个数组与一个数进行运算操作

# -*- coding:utf-8 -*-
import numpy as np

arr1 = np.array([4,6,8,10])
print('一维数组的标量运算')
print('加:',arr1+2)
print('减:',arr1-2)
print("乘: " ,arr1*2)
print("除: " ,arr1/2)

arr1 = np.array([[4,6],[8,9]])
print('二维数组的标量运算')
print('加:',arr1+2)
print('减:',arr1-2)
print("乘: " ,arr1*2)
print("除: " ,arr1/2)

数学函数

# -*- coding:utf-8 -*-
import numpy as np


arr1 = np.array([[1,2],[-3,-4]])
print('arr1:\n',arr1)
print('求平方:\n',np.square(arr1))
print('求绝对值:\n',np.abs(arr1))

arr2 = np.array([[1.2,3.5],[3.6,4.4]])
print('arr2:\n',arr2)
print("求四舍五入值:\n " ,np.around(arr2))

arr3 = np.array([2,1.2,2.8,-0.5,-1.9,-2.1])
print('arr3:\n',arr3)
print("向上取整:\n " ,np.ceil(arr3))
print("向下取整:\n " ,np.floor(arr3))

学习参考资料：《从0到1Python数据分析》