小白学Python——Matplotlib 学习（3） 函数图形

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-1,1,50)
y = 2*x + 1

plt.figure()
plt.plot(x,y)
plt.show()

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-10,10,50)

y1 = 2*x + 1
y2 = x**2

plt.figure()
plt.plot(x,y1)
plt.plot(x,y2)
plt.show()

　　

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-10,10,50)

y1 = 2*x + 1
y2 = x**2

plt.figure()
plt.plot(x,y1,label='straight line')
plt.plot(x,y2,linestyle='dashed',linewidth=0.5,color='red',marker='.',label='square line')
plt.legend()
plt.ylim(-1,4)
plt.xlim(-3,3)
ax = plt.gca()
ax.spines['top'].set_color('none')
ax.spines['right'].set_color('none')
ax.spines['left'].set_position(('data',0))
ax.spines['bottom'].set_position(('data',0))
plt.show()

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(-10,10,50)

y1 = 2*x + 1
y2 = x**2

plt.figure()
plt.plot(x,y1,label='straight line')
plt.plot(x[:35],y2[:35],linestyle='dashed',linewidth=0.5,color='red',label='square line')
plt.plot([1,1],[0,3],'k--')
plt.scatter([1,],[3,],s=20,color='blue')
plt.annotate('emphasize point',xy=(1,3),xytext=(15,-15),textcoords='offset pixels',arrowprops=dict(arrowstyle='<|-', connectionstyle="arc3,rad=.2"))
plt.text(-2.4, 6, 'This is some text',fontdict={'size': 16, 'color': 'r'})
plt.legend(loc='best')
ax = plt.gca()
ax.spines['top'].set_color('none')
ax.spines['right'].set_color('none')
ax.spines['left'].set_position(('data',0))
ax.spines['bottom'].set_position(('data',0))
plt.show()