Matplotlib：设置坐标轴

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-3,3,50)
y1 = x3
y2 = x2+2*x+2
#第一个图像
plt.figure()
plt.plot(x,y1,color=‘red’,linestyle=’–’)
#第二个图像
plt.figure()
plt.plot(x,y1)
plt.plot(x,y2,color=‘blue’,linestyle=’–’)

plt.xlim((-4,3)) #修改x和y的值
plt.ylim((-3,3))
plt.xlabel(‘I am X’)
plt.ylabel(‘I am Y’)

new_ticks = np.linspace(-1,2,5)#修改x坐标轴
plt.xticks(new_ticks)
plt.yticks([-2,-1,0,1,2],
[‘really bad’,r’$bad//alpha$bad//alpha’,‘normal’,‘good’,‘very good’])

#设置四个边界
ax = plt.gca() #get current axis
ax.spines[‘right’].set_color(‘none’)#将右边框去除
ax.spines[‘top’].set_color(‘none’)
ax.xaxis.set_ticks_position(‘bottom’)#将底部边框设置为X轴
ax.yaxis.set_ticks_position(‘left’)
ax.spines[‘bottom’].set_position((‘data’,0))#两个对齐点为0
ax.spines[‘left’].set_position((‘data’,0))