Python 之 matplotlib (三)坐标轴

代码：

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-3, 3, 50)
y1 = 2 * x + 1
y2 = x ** 2
plt.figure()
plt.plot(x, y2)
plt.plot(x, y1, color='red', linewidth=1.0, linestyle='--')
# 设置坐标轴取值范围
plt.xlim((-1, 2))
plt.ylim((-2, 3))
# 标签
plt.xlabel('I am X')
plt.ylabel('I am y')
# 换坐标轴角标 字体
new_ticks = np.linspace(-1, 2, 5)
print(new_ticks)
plt.xticks(new_ticks)
plt.yticks([-2, -1.8, -1, 1.22, 3],
           ['$really\ bad$', r'$bad\ \alpha$', r'$normal$', r'$good$', r'$really/ good$'])
# 修改坐标轴位置
ax = plt.gca()
ax.spines['right'].set_color('none')
ax.spines['top'].set_color('none')
ax.xaxis.set_tick_params('bottom')
ax.yaxis.set_tick_params('left')
ax.spines['bottom'].set_position(('data', -1))
ax.spines['left'].set_position(('data', 0))
plt.show()

运行结果：