Modified scientific notation in colorbar ticks

Question

i would like to place two ticks in my colorbar. matplotlib.

my problem is at the format of the numbers at the colorbar. I would like instead of 1.99e+00 to have 1.9e0 . Better would be if the number would be rounded (eg 2.0e0 )

The number 0 should stay as 0 .

here is the code:

from scipy import *
import matplotlib.pylab as plt
import numpy as np

def main():
# Creating the grid of coordinates x,y 
x,y = ogrid[-1.:1.:.01, -1.:1.:.01]

z = 3*y*(3*x**2-y**2)/4 + .5*cos(6*pi * sqrt(x**2 +y**2) + arctan2(x,y))

fig = plt.figure()

ax = fig.add_subplot(111)
result = ax.imshow(z, 
                   origin='lower', 
                   extent=[0,2,0,400],              
           interpolation='nearest',
           aspect='auto'
          )
cbar = fig.colorbar( result , ticks=[ 0 , z.max() ])
    cbar.ax.set_yticklabels([ 0 ,  '{0:.2e}'.format( z.max()) ]) 
    cbar.outline.remove()

plt.show()

if __name__ == '__main__':
    main()

Answer 1

The format you're using can be trivially modified to be one digit after the decimal instead of two, which automatically includes rounding. The other changes you want are easy too if you do them as text modifications.

def format_yticklabel(number):
    return '{0:.1e}'.format(number).replace('+0', '').replace('-0', '-')

>>> format_yticklabel(1.99)
'2.0e0'