python 可视化 散点图。柱状图、等高线

import matplotlib.pyplot as plt

import numpy as np

#n个点

n = 1024

#平均值是0，方差是1

X = np.random.normal(0,1,n)

Y = np.random.normal(0,1,n)

#确定颜色

T = np.arctan2(Y,X)

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

#plt.scatter(np.arange(5),np.arange(5))

plt.xlim(-1.5,1.5)

plt.ylim(-1.5,1.5)

#隐藏所有的ticks

plt.xticks(())

plt.yticks(())

plt.show()

import matplotlib.pyplot as plt

import numpy as np

#12个柱状图

n=12

X = np.arange(n)#x会生成0到11

Y1 = (1-X/float(n))*np.random.uniform(0.5, 1.0, n)#随机随机生成0.5到1的数

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')

#zip是把X，Y1中的值分别给x和y

#plt.text(x位置，y位置，值）

for x,y in zip(X,Y1):

    #ha:horizontal alignment对齐方式

    plt.text(x,y+0.05,'%.2f' % y,ha='center',va='bottom')

for x,y in zip(X,Y2):

    #ha:horizontal alignment对齐方式

    plt.text(x,-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()

import matplotlib.pyplot as plt

import numpy as np

#通过x，y计算高度

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)

#把x，y绑定成网格的输入值

X,Y = np.meshgrid(x,y)

# use plt.contourf to filling contours

#X,Y and value for (X,Y) point

#contour为网格

#8代表分成10部分

#0分成2部分

#plt.cm.cool为冷色调,plt.cm.hot为暖色调,plt.cm.Spectral,plt.cm.hsv,plt.cm.ocean

plt.contourf(X,Y,f(X,Y),8,alpha=0.75,cmap=plt.cm.hsv)#画上颜色

#use plt.contour to add contounlines

#画线,contour为等高线的线

C = plt.contour(X,Y,f(X,Y),8,colors='black',linwidth=.5)

#adding label

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

plt.xticks(())

plt.yticks(())

plt.show()

import matplotlib.pyplot as plt

import numpy as np

#image data

a = np.array([4.11360827978,3.365348418405,2.423766120134,

              3.365248418405,2.39599930621,1.525083754405,

              2.423733120134,1.525083754405,0.651536351379]).reshape(3,3)

plt.imshow(a,interpolation='nearest',cmap='bone',origin='upper')

plt.colorbar(shrink=0.9)#shrink压缩，0.9压缩90%

plt.xticks(())

plt.yticks(())

plt.show()