Example of how to replace the default log-plot exponential labels with integer labels. The same method will work for any kind of custom labeling. This example was pulled from the Python-list mailing list and the original can be found here.

   1 from pylab import *
   2 
   3 def log_10_product(x, pos):
   4     """The two args are the value and tick position.
   5     Label ticks with the product of the exponentiation"""
   6     return '%1i' % (x)
   7 
   8 # Axis scale must be set prior to declaring the Formatter
   9 # If it is not the Formatter will use the default log labels for ticks.
  10 ax = subplot(111)
  11 ax.set_xscale('log')
  12 ax.set_yscale('log')
  13 
  14 formatter = FuncFormatter(log_10_product)
  15 ax.xaxis.set_major_formatter(formatter)
  16 ax.yaxis.set_major_formatter(formatter)
  17 
  18 # Create some artificial data.
  19 result1 = [3, 5, 70, 700, 900]
  20 result2 = [1000, 2000, 3000, 4000, 5000]
  21 predict1 = [4, 8, 120, 160, 200]
  22 predict2 = [2000, 4000, 6000, 8000, 1000]
  23 
  24 # Plot
  25 ax.scatter(result1, predict1, s=40, c='b', marker='s', faceted=False)
  26 ax.scatter(result2, predict2, s=40, c='r', marker='s', faceted=False)
  27 
  28 ax.set_xlim(1e-1, 1e4)
  29 ax.set_ylim(1e-1, 1e4)
  30 grid(True)
  31 
  32 xlabel(r"Result", fontsize = 12)
  33 ylabel(r"Prediction", fontsize = 12)

Cookbook/Matplotlib/CustomLogLabels (last edited 2008-09-17 01:38:37 by jesrl)