matplotlib-users Mailing List for matplotlib

On Sunday 16 July 2006 19:38, Webb Sprague wrote:
> I have data with missing values represented by nans (like array([1.0,
> nan, 3.0]) that I am plotting with pylab.semilogy().
Please transform your array in a MaskedArray.
import numpy as N
masked_x=N.ma.masked_where(N.isnan(x),x)
That should do the trick.
Cf http://www.scipy.org/Cookbook/Matplotlib/Plotting_values_with_masked_arrays

I have data with missing values represented by nans (like array([1.0,
nan, 3.0]) that I am plotting with pylab.semilogy(). Unfortunately,
the lines are getting connected through the nans, while I was hoping
they would be left empty. If someone could tell me how to get empty
lines, that would be great.
I get the behavior I expect with pylab.plot(), so if I need to I can
transform the data first, but I would rather get the log y-axis from
semilogy.
I am running version matplotlib 0.87.3 on Gentoo linux.
Thanks!

Works like a champ.
Thank you, S.
John Hunter wrote:
>>>>>> "Simon" == Simon Hook <sim...@jp...> writes:
>>>>>> 
>
> Simon> Hi, [cross posted to egenix and matplotlib]
>
> Simon> I have been using the egenix mxDateTime module and want to
> Simon> plot some of the dates with Matplotlib (pylab). Pylab uses
> Simon> num2date and date2num to covert datesandtimes to floating
> Simon> point values for plotting. Unfortunately if you give pylab
> Simon> date2num an egenix DateTime object, pylab bombs. Is there a
> Simon> simple way to use egenix DateTime objects with Pylab?
>
> See matplotlib.dates.mx2num
>
> JDH
> 

Simon Hook wrote:
> Hi,
> 
> [cross posted to egenix and matplotlib]
> 
> I have been using the egenix mxDateTime module and want to plot some of
> the dates with Matplotlib (pylab). Pylab uses num2date and date2num to
> covert datesandtimes to floating point values for plotting.
> Unfortunately if you give pylab date2num an egenix DateTime object,
> pylab bombs. Is there a simple way to use egenix DateTime objects with
> Pylab?
> 
> Below is a simple example
> 
> #D:\apps\Python23\python.exe
> 
> from datetime import *
> from mx.DateTime import *
> from pylab import *
> 
> # This works
> a=datetime(2005,10,10,5,5,5)
> print a
> 
> # This works
> b=DateTime(2005,10,10,5,5,5)
> print b
> 
> # This works
> c=date2num(a)
> print c
> 
> # This fails
> d=date2num(b)
> print d
> 
> The output and failure message is:
> 
> 2005年10月10日 05:05:05
> 2005年10月10日 05:05:05.00
> 732229.211863
I'm not sure what date2num() uses as epoch, but it looks like
some variant of a Julian Day Number:
>>> b.jdn
2453653.711863426
>>> b.tjd
3653.2118634259259
> Traceback (most recent call last):
> File "datetime-problem.py", line 20, in ?
> d=date2num(b)
> File "D:\apps\Python23\lib\site-packages\matplotlib\dates.py", line
> 174, in da
> te2num
> if not iterable(d): return _to_ordinalf(d)
> File "D:\apps\Python23\lib\site-packages\matplotlib\dates.py", line
> 137, in _t
> o_ordinalf
> base = dt.toordinal()
> AttributeError: toordinal
.toordinal() is a datetime method which is not supported by mxDateTime
instances.
-- 
Marc-Andre Lemburg
eGenix.com
Professional Python Services directly from the Source (#1, Jul 16 2006)
>>> Python/Zope Consulting and Support ... http://www.egenix.com/
>>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/
>>> mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/
________________________________________________________________________
::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,FreeBSD for free ! ::::

>>>>> "Simon" == Simon Hook <sim...@jp...> writes:
 Simon> Hi, [cross posted to egenix and matplotlib]
 Simon> I have been using the egenix mxDateTime module and want to
 Simon> plot some of the dates with Matplotlib (pylab). Pylab uses
 Simon> num2date and date2num to covert datesandtimes to floating
 Simon> point values for plotting. Unfortunately if you give pylab
 Simon> date2num an egenix DateTime object, pylab bombs. Is there a
 Simon> simple way to use egenix DateTime objects with Pylab?
See matplotlib.dates.mx2num
JDH

Hi,
[cross posted to egenix and matplotlib]
I have been using the egenix mxDateTime module and want to plot some of 
the dates with Matplotlib (pylab). Pylab uses num2date and date2num to 
covert datesandtimes to floating point values for plotting. 
Unfortunately if you give pylab date2num an egenix DateTime object, 
pylab bombs. Is there a simple way to use egenix DateTime objects with 
Pylab?
Below is a simple example
#D:\apps\Python23\python.exe
from datetime import *
from mx.DateTime import *
from pylab import *
# This works
a=datetime(2005,10,10,5,5,5)
print a
# This works
b=DateTime(2005,10,10,5,5,5)
print b
# This works
c=date2num(a)
print c
# This fails
d=date2num(b)
print d
The output and failure message is:
2005年10月10日 05:05:05
2005年10月10日 05:05:05.00
732229.211863
Traceback (most recent call last):
 File "datetime-problem.py", line 20, in ?
 d=date2num(b)
 File "D:\apps\Python23\lib\site-packages\matplotlib\dates.py", line 
174, in da
te2num
 if not iterable(d): return _to_ordinalf(d)
 File "D:\apps\Python23\lib\site-packages\matplotlib\dates.py", line 
137, in _t
o_ordinalf
 base = dt.toordinal()
AttributeError: toordinal
thanks, Simon