坐标轴设置02--python库--matplotlib

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-3,3,50)#从-3到3设置50个点
#设置两个函数
y1 = 2 * x + 1
y2 = x ** 2

plt.figure()
plt.plot(x,y2)
plt.plot(x,y1,color = 'red',linewidth = 1.0,linestyle = '--')

plt.xlim((-1,2))#设置坐标轴
plt.ylim((-2,3))
plt.xlabel('I am x')#解释坐标轴信息
plt.ylabel('I am y')

new_ticks = np.linspace(-1,2,5)
print(new_ticks)
plt.xticks(new_ticks)#改变坐标轴的显示
# plt.yticks([-2,-1.8,-1,1.22,3]
#            ,['really bad','bad','normal','good','really good'])


plt.yticks([-2,-1.8,-1,1.22,3]
           ,[r'$really\ bad$','$bad$','$normal$','$good$','$really\ good$'])#设置斜体字体
#方法：\加表示方式如数学的 阿尔法  \alpha


#gca = 'get current axis'获取当前坐标轴
ax = plt.gca()
ax.spines['right'].set_color('none')#将右坐标轴设置为空
ax.spines['top'].set_color('none')
# ax.xaxis.set_ticks_position('bottom')#将下坐标轴设置为x轴
# ax.xaxis.set_ticks_position('left')
ax.spines['bottom'].set_position(('data',0))#设置起点，也可以用axes参数为百分比
ax.spines['left'].set_position(('data',0))
print('123')



plt.show()