[Matplotlib-users] histogram creation tidbits

[Finny K. <kur...@mo...>]

I've finally figured out why I've been having trouble creating histograms=
.
 As it turns out, if you pass to hist() a datatype that is numpy.ndarray
instead of a Numeric array, you get the following error.  Check this out:

>>> import numpy
>>> import Numeric
>>> from pylab import *
>>> y=3DNumeric.array([1,2])
>>> hist(y)       # This works no problem
>>> x=3Dnumpy.array([1,2])
>>> hist(x)
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/lib/python2.4/site-packages/matplotlib/pylab.py", line 1857,
in hist
    ret =3D  gca().hist(*args, **kwargs)
  File "/usr/lib/python2.4/site-packages/matplotlib/axes.py", line 1676,
in hist
    n,bins =3D matplotlib.mlab.hist(x, bins, normed)
  File "/usr/lib/python2.4/site-packages/matplotlib/mlab.py", line 621, i=
n
hist
    dy =3D (ymax-ymin)/bins
TypeError: unsupported operand type(s) for -: 'str' and 'str'


I'm not exactly sure why this is true, but I've empirically found this ou=
t
to be the case.  If anyone knows why, I'd sure love to know.

Thanks,
Finny Kuruvilla