Re: [Matplotlib-users] How to use logarithmic scale with histogram?

[<jk...@ik...>]

"Mika Orajärvi" <mik...@gm...> writes:

> This code does seem to draw some kind of histogram but it would be
> much more usefull to have at least the y-scale as logarithmic. But I
> haven't found a way to make the scale logarithmic.

According to the docstring of hist you can give it a keyword argument
of log=True to make the y axis logarithmic. However there is a slight
bug in that zero-height histogram bars like you have in your example
cause log(0) to be computed. Here's a quick fix:

------------------------------------------------------------------------
from pylab import *
x=0.000925,0.000879,0.000926,0.00088,0.001016,0.000931,0.000927,0.00088,\
  0.000926,0.000926,0.000879,0.0009
n, bins = mlab.hist(x, 1000)
width = 0.9 * (bins[1]-bins[0])
nz = nonzero(n)
bar(bins[nz], n[nz], width=width, log=True)
grid(True)
show()
------------------------------------------------------------------------

If the devs agree that this is a bug in hist, I can fix it in svn.

-- 
Jouni K. Seppänen
http://www.iki.fi/jks