python画圆运用了matplotlb库的figure()和Circle()函数；其中，figure()函数用于确定画布大小，而Circle()函数用于配置圆的相关信息，进而画圆。
本教程操作环境：windows7系统、Python3版、Dell G3电脑。
python画圆代码from matplotlib.patches import Ellipse, Circle
import matplotlib.pyplot as plt
def plot_cicle():
fig = plt.figure()
ax = fig.add_subplot(111)
cir1 = Circle(xy = (0.0, 0.0), radius=2, alpha=0.5)
ax.add_patch(cir1)
x, y = 0, 0
ax.plot(x, y, ‘ro’)
plt.axis(‘scaled’)
plt.axis(‘equal’) #changes limits of x or y axis so that equal increments of x and y have the same length
plt.show()
plot_cicle()
