matplotlib入门（二）

scatter散点图

import matplotlib.pyplot as plt
import numpy as np

n = 1024
X = np.random.normal(0,1,n)
Y = np.random.normal(0,1,n)
T = np.arctan2(Y,X) #for color value

plt.scatter(X,Y,s=75,c=T,alpha=0.5)

plt.xlim((-1.5,1.5))
plt.ylim((-1.5,1.5))
#plt.xticks(())
#plt.yticks(())

plt.show()

bar柱状图

import matplotlib.pyplot as plt
import numpy as np

n = 12
X = np.arange(n)
Y1 = (1-X/float(n))*np.random.uniform(0.5,1.0,n)
Y2 = (1-X/float(n))*np.random.uniform(0.5,1.0,n)

plt.bar(X,+Y1,facecolor='#9999ff',edgecolor='white')
plt.bar(X,-Y2,facecolor='#ff9999',edgecolor='white')


for x,y in zip(X,Y1):
    #ha:horizional alignment
    plt.text(x+0.04,y+0.05,'%.2f'%y,ha='center',va='bottom')

for x,y in zip(X,Y2):
    plt.text(x+0.04,-y-0.05,'-%.2f'%y,ha='center',va='top')
plt.xlim(-.5,n)
plt.xticks(())
plt.ylim(-1.25,1.25)
plt.yticks(())
plt.show()

contours等高线图

import matplotlib.pyplot as plt
import numpy as np

def f(x,y):
    return (1-x/2+x**5+y**3)*np.exp(-x**2-y**2)
n=256
x=np.linspace(-3,3,n)
y=np.linspace(-3,3,n)
X,Y = np.meshgrid(x,y)

plt.contourf(X,Y,f(X,Y),8,alpha=0.75,cmap=plt.cm.hot)
C = plt.contour(X,Y,f(X,Y),8,colors='black',linewidth=.5)

plt.clabel(C,inline=True,fontsize=10)
plt.xticks(())
plt.yticks(())
plt.show()

Image图片

import matplotlib.pyplot as plt
import numpy as np
#img data
a=np.array([0.313660827978,0.365348418405,0.423733120134,0.365348418405,0.439599930621,0.525083754405,0.423733120134,0.525083754405,0.651536351379]).reshape(3,3)

plt.imshow(a,interpolation='nearest',cmap='bone',origin='upper')
plt.colorbar(shrink=0.9) #参数：压缩到原来90%
plt.xticks(())
plt.yticks(())
plt.show()

3D数据

import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.mplot3d import Axes3D

fig = plt.figure()
ax = Axes3D(fig)

X = np.arange(-4,4,0.25)
Y = np.arange(-4,4,0.25)
X,Y = np.meshgrid(X,Y)
R = np.sqrt(X**2+Y**2)
Z = np.sin(R)

ax.plot_surface(X,Y,Z,rstride=1,cstride=1,cmap=plt.get_cmap('rainbow'))
ax.contourf(X,Y,Z,zdir='x',offset=-4,cmap='rainbow')
ax.set_zlim(-2,2)
plt.show()