python matplotlib彩条设置刻度格式或定位器更改刻度标签

Question

用户， 我想定制颜色条上的刻度。但是，我发现了以下奇怪的行为。我尝试将刻度格式更改为默认格式（我认为这应该不会改变任何内容），但我最终得到了不同的标签。有人知道我做错了什么吗？或者这是一个错误？

我使用git（v1.0.1-961-gb516ae0，git describe）中的matplotlib。 以下代码产生两个图：

#http://matplotlib.sourceforge.net/examples/pylab_examples/griddata_demo.html 
from numpy.random import uniform, seed 
from matplotlib.mlab import griddata 
import matplotlib.pyplot as plt 
import matplotlib.ticker 
import numpy as np 
# make up data. 
seed(0) 
npts = 200 
x = uniform(-2,2,npts) 
y = uniform(-2,2,npts) 
z = x*np.exp(-x**2-y**2) 
# define grid 
xi = np.linspace(-2.1,2.1,100) 
yi = np.linspace(-2.1,2.1,200) 
# grid the data. 
zi = griddata(x,y,z,xi,yi,interp='linear') 

##### FIRST PLOT 
plt.figure() 
CS = plt.contour(xi,yi,zi,25,cmap=plt.cm.jet) 
bar = plt.colorbar() # draw colorbar 
# plot data points. 
#plt.scatter(x,y,marker='o',c='b',s=5,zorder=10) 
plt.xlim(-2,2) 
plt.ylim(-2,2) 
plt.title('griddata test (%d points)' % npts) 
plt.show() 

##### SECOND PLOT 
plt.figure() 
CS = plt.contour(xi,yi,zi,25,cmap=plt.cm.jet) 
bar = plt.colorbar() # draw colorbar 
bar.ax.yaxis.set_minor_locator(matplotlib.ticker.AutoLocator()) 
bar.ax.yaxis.set_major_locator(matplotlib.ticker.AutoLocator()) 
# plot data points. 
#plt.scatter(x,y,marker='o',c='b',s=5,zorder=10) 
plt.xlim(-2,2) 
plt.ylim(-2,2) 
plt.title('griddata test (%d points)' % npts) 
plt.show() 

Answer 1

我刚找到解决方案。一个人打电话给

bar.update_ticks() 

的formators后

/定位器改变，见

http://matplotlib.sourceforge.net/api/colorbar_api.html

然后一切正常。

更新：

这里也是这改变了Formator /定位器的代码。它基于colorbar-code的内部结构，所以也许别人有更好的解决方案：

#http://matplotlib.sourceforge.net/examples/pylab_examples/griddata_demo.html 
from numpy.random import uniform, seed 
from matplotlib.mlab import griddata 
import matplotlib.pyplot as plt 
import matplotlib.ticker 
import numpy as np 
# make up data. 
seed(0) 
npts = 200 
x = uniform(-2,2,npts) 
y = uniform(-2,2,npts) 
z = x*np.exp(-x**2-y**2) 
# define grid 
xi = np.linspace(-2.1,2.1,100) 
yi = np.linspace(-2.1,2.1,200) 
# grid the data. 
zi = griddata(x,y,z,xi,yi,interp='linear') 

##### PLOT 
plt.figure() 
CS = plt.contour(xi,yi,zi,25,cmap=plt.cm.jet) 
bar = plt.colorbar(orientation='horizontal') # draw colorbar 


tick_locs = [-3.9e-1,-2.6e-1,-1.3e-1,0e-1,1.3e-1,2.6e-1,3.9e-1] 
tick_labels = ['-0.390','-0.260','-0.130','0','0.13','0.26','0.390'] 


bar.locator  = matplotlib.ticker.FixedLocator(tick_locs) 
bar.formatter = matplotlib.ticker.FixedFormatter(tick_labels) 
bar.update_ticks() 

# plot data points. 
#plt.scatter(x,y,marker='o',c='b',s=5,zorder=10) 
plt.xlim(-2,2) 
plt.ylim(-2,2) 
plt.title('griddata test (%d points)' % npts) 
plt.show()