matplotlib改變colorbar位置和方向

#! usr/bin/python
#coding=utf-8 
import numpy as np
import matplotlib.pyplot as plt 
data=np.random.rand(10,10)
fig, ax=plt.subplots()
data[data==-1]=np.nan#去掉缺省值-1
im =ax.imshow(data,interpolation='none',cmap='Reds_r',vmin=0.6,vmax=.9)#不插值
#去掉邊框
ax.spines['top'].set_visible(False)
ax.spines['right'].set_visible(False)
ax.spines['bottom'].set_visible(False)
ax.spines['left'].set_visible(False)
########################################################################
position=fig.add_axes([0.15, 0.05, 0.7, 0.03])#位置[左,下,右,上]
cb=plt.colorbar(im,cax=position,orientation='horizontal')#方向