from __future__ import print_function # -*- coding: utf-8 -* import numpy as np a = np.array([2, 0, 1, 5]) print(a) # 打印数组 print(a[:3]) # 切片，输出前三个元素 print(a.max()) a.sort() print(a) b = np.array([[1,2,3], [4,5,6]]) print(b * b) ### 随机散点图 ### from matplotlib import pyplot as plt from mpl_toolkits.mplot3d import Axes3D #定义坐标轴 fig4 = plt.figure() ax4 = plt.axes(projection= '3d') #生成三维数据 xx = np.random.random( 20)* 10- 5#取100个随机数，范围在5~5之间 yy = np.random.random( 20)* 10- 5 X, Y = np.meshgrid(xx, yy) Z = np.sin(np.sqrt(X** 2+Y** 2)) #作图 ax4.scatter(X,Y,Z,alpha= 0.3,c=np.random.random( 400),s=np.random.randint( 10, 20, size=( 20, 40))) #生成散点.利用c控制颜色序列,s控制大小 #设定显示范围 plt.show()