matplotlib-users Mailing List for matplotlib (Page 4)

Dear matplotlib users,
I would like to know if there is in matplotlib the following Matlab
function:
*p=patch(x(TRI'),y(TRI'),u(TRI'),u(TRI'));*
*set(p,'FaceColor','interp','EdgeColor','black');*
where TRI are the coordinate of many non regular rectangles.
I would like to do that because I have a not-structured grid whose elements
are irregular rectangles. I would like to plot a 3D surface of the values
on each points of the grid.
Thanks in advance to everyone

Hi Jody,
what exactly du you mean - the plot windows size?
I tried this:
fig = plt.figure(figsize=(8.4,5.76))
But still the same problem.
Regards 
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On 2014年12月04日 15:40, Joe Kington wrote:
> Nbagg is non-interactive, similar to Agg. No events other than draw events
> are supported, as far as I know.
	If that's the case, the release notes should probably make that clear. 
 Right now at 
http://matplotlib.org/users/whats_new.html#the-nbagg-backend it says: 
"Phil Elson added a new backend, named "nbagg", which enables 
interactive figures in a live IPython notebook session." The word 
"interactive" certainly could lead people to believe that the backend 
is, in fact, interactive.
-- 
Brendan Barnwell
"Do not follow where the path may lead. Go, instead, where there is no 
path, and leave a trail."
 --author unknown

Hi
Your code wans't included, but try setting your x and y limits *before* the call to clabel. I think that the problem is that clabel makes a space in the contours according to how large your font is, but if you then resize the plot (zoom in) then the blank space is too large for the labels. 
Cheers, Jody
> On Dec 4, 2014, at 17:47 PM, Sappy85 <rob...@gm...> wrote:
> 
> I have trouble with matplotlib / pyplot / basemap. I plot contour lines (air
> pressure) on a map. I use clabel to show the value of the contour lines. But
> the problem: the padding between the value and the contour line is too much.
> I have found the parameter "inline_spacing", which i have set to zero. But
> there is still to much free space. Any ideas?
> 
> <http://matplotlib.1069221.n5.nabble.com/file/n44554/mslp.png> 
> 
> My code is as follows:
> 
> 
> 
> 
> Thanks a lot. 
> 
> 
> 
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I have trouble with matplotlib / pyplot / basemap. I plot contour lines (air
pressure) on a map. I use clabel to show the value of the contour lines. But
the problem: the padding between the value and the contour line is too much.
I have found the parameter "inline_spacing", which i have set to zero. But
there is still to much free space. Any ideas?
<http://matplotlib.1069221.n5.nabble.com/file/n44554/mslp.png> 
My code is as follows:
Thanks a lot. 
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Thanks for the response Joe.
I guess keyboard events are just not implemented yet.
Mouse events (at least button_press_event) do seem to work.
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Nbagg is non-interactive, similar to Agg. No events other than draw events
are supported, as far as I know.
I think there are long term plans to change that (eg, webagg and
mplh5canvas), but it's a fairly tricky problem.
How that helps clarify why things aren't working, anyway.
-Joe
On Dec 4, 2014 11:04 AM, "reem17" <elwin@u.northwestern.edu> wrote:
> I'm using matplotlib version 1.4.2 on linux and am having trouble getting
> key
> event
> callbacks when using the nbagg backend in an ipython notebook (i've tried
> in
> firefox and chromium).
> The key press events seem to not be processed (no matter what key I try to
> press). This code does work with the qt backend.
>
> %matplotlib nbagg
> import matplotlib.pyplot as plt
> f=plt.figure()
> plt.plot([1,2,3,4])
> def handler(event):
> plt.plot([4,3,2,1])
> f.canvas.mpl_connect('key_press_event',handler);
>
>
> Thanks for any help.
>
>
>
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I'm using matplotlib version 1.4.2 on linux and am having trouble getting key
event
callbacks when using the nbagg backend in an ipython notebook (i've tried in
firefox and chromium).
The key press events seem to not be processed (no matter what key I try to
press). This code does work with the qt backend.
%matplotlib nbagg
import matplotlib.pyplot as plt
f=plt.figure()
plt.plot([1,2,3,4])
def handler(event):
 plt.plot([4,3,2,1])
f.canvas.mpl_connect('key_press_event',handler);
Thanks for any help. 
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Hello,
try doing:
import matplotlib.pyplot as plt
import random
rolls = list()
for i in range(1000):
 rolls.append(random.randint(1,6))
plt.hist(rolls, bins=6)
plt.show()
Reason why your histogram is weird is because you only can have 6 bins
in your example. But the default bin number for hist function is 10.
The borders of bins are therefore set at half intervals. When you roll
1, bin 0 to 0.6 gets incremented, when you roll 2.2 bin 2-2.6 gets
incremented, but the bin 0.6-2.2 never does.
Follow me? (also I just made those numbers up...) Point is only the
bottom bins of your roll values are filled which leaves a gap in your
image.
Dino
2014年12月03日 21:51 GMT+01:00 Amit Saha <ami...@gm...>:
> On Thu, Dec 4, 2014 at 6:45 AM, Brendan Barnwell <bre...@br...> wrote:
>> On 2014年12月03日 12:39, Amit Saha wrote:
>>>
>>> Hi,
>>>
>>> Please find attached a simple histogram created using the hist()
>>> function. Any idea why the last two bars are squeezed into each other?
>>> Is there a simple way to fix this while plotting?
>>
>>
>> It looks like the bins are set up so that there are empty bins
>> between each of the other bars. How are you setting the bins? You could
>> try adjusting the bin boundaries.
>
> Thanks for the reply. This is my program:
>
> import matplotlib.pyplot as plt
> import random
>
> def roll():
> return random.randint(1, 6)
>
> if __name__ == '__main__':
> rolls = []
> for i in range(1000):
> rolls.append(roll())
> # create a histogram plot
> plt.hist(rolls)
> plt.show()
>
>
> So, just using the hist() function for now.
>
> Thanks, Amit.
>
>>
>> --
>> Brendan Barnwell
>> "Do not follow where the path may lead. Go, instead, where there is no
>> path, and leave a trail."
>> --author unknown
>
>
>
> --
> http://echorand.me
>
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On Thu, Dec 4, 2014 at 6:45 AM, Brendan Barnwell <bre...@br...> wrote:
> On 2014年12月03日 12:39, Amit Saha wrote:
>>
>> Hi,
>>
>> Please find attached a simple histogram created using the hist()
>> function. Any idea why the last two bars are squeezed into each other?
>> Is there a simple way to fix this while plotting?
>
>
> It looks like the bins are set up so that there are empty bins
> between each of the other bars. How are you setting the bins? You could
> try adjusting the bin boundaries.
Thanks for the reply. This is my program:
import matplotlib.pyplot as plt
import random
def roll():
 return random.randint(1, 6)
if __name__ == '__main__':
 rolls = []
 for i in range(1000):
 rolls.append(roll())
 # create a histogram plot
 plt.hist(rolls)
 plt.show()
So, just using the hist() function for now.
Thanks, Amit.
>
> --
> Brendan Barnwell
> "Do not follow where the path may lead. Go, instead, where there is no
> path, and leave a trail."
> --author unknown
-- 
http://echorand.me

On 2014年12月03日 12:39, Amit Saha wrote:
> Hi,
>
> Please find attached a simple histogram created using the hist()
> function. Any idea why the last two bars are squeezed into each other?
> Is there a simple way to fix this while plotting?
	It looks like the bins are set up so that there are empty bins between 
each of the other bars. How are you setting the bins? You could try 
adjusting the bin boundaries.
-- 
Brendan Barnwell
"Do not follow where the path may lead. Go, instead, where there is no 
path, and leave a trail."
 --author unknown

Hi,
Please find attached a simple histogram created using the hist()
function. Any idea why the last two bars are squeezed into each other?
Is there a simple way to fix this while plotting?
Thanks,
Amit.

Ok, then this looks like a legitimate bug in span_where(). It probably
isn't applying units, somehow. This isn't really a problem with pandas, it
is an issue where we aren't being consistent in applying units for all
plotting functions. Could you file a bug report, please?
Cheers!
Ben Root
On Tue, Dec 2, 2014 at 11:15 AM, Fabien <fab...@gm...> wrote:
> On 02.12.2014 16:59, Benjamin Root wrote:
> > Does the workaround posted here fix things for you?
> >
> https://github.com/matplotlib/matplotlib/issues/3727#issuecomment-60899590
>
> sorry it doesn't.
>
> I updated the test case below (including the workaround, I hope I got it
> right). The strange thing is that fill_between() works fine, but
> pan_where() is the problem.
>
> Thanks!
>
> #-------------------------------------------
> import pandas as pd
> import numpy as np
> from datetime import datetime as dt
> import matplotlib.pyplot as plt
> import matplotlib.collections as collections
> span_where = collections.BrokenBarHCollection.span_where
> import matplotlib.units as units
>
> units.registry[np.datetime64] = pd.tseries.converter.DatetimeConverter()
>
> # init the dataframe
> time = pd.date_range(pd.datetime(1950,1,1), periods=5, freq='MS')
> df = pd.DataFrame(np.arange(5), index=time, columns=['data'])
> df['cond'] = df['data'] >= 3
>
> # This is working (but its not what I want)
> x = np.arange(5)
> fig = plt.figure()
> ax = fig.add_subplot(111)
> plt.plot(x, df['data'], 'k')
> c = span_where(x, ymin=0, ymax=4, where=df['cond'], color='green')
> ax.add_collection(c)
> plt.show()
>
> #This is not
> x = df.index.values
> fig = plt.figure()
> ax = fig.add_subplot(111)
> plt.plot(x, df['data'], 'k')
> c = span_where(x, ymin=0, ymax=4, where=df['cond'], color='green')
> ax.add_collection(c)
> plt.show()
>
> #This is producing an error
> x = df.index
> fig = plt.figure()
> ax = fig.add_subplot(111)
> plt.plot(x, df['data'], 'k')
> c = span_where(x, ymin=0, ymax=4, where=df['cond'], color='green')
> ax.add_collection(c)
> plt.show()
> #-------------------------------------------
>
>
>
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OK I just filled a bug report:
https://github.com/matplotlib/matplotlib/issues/3872
my first bug report ever!
On 02.12.2014 17:15, Fabien wrote:
> On 02.12.2014 16:59, Benjamin Root wrote:
>> Does the workaround posted here fix things for you?
>> https://github.com/matplotlib/matplotlib/issues/3727#issuecomment-60899590
>
> sorry it doesn't.
>
> I updated the test case below (including the workaround, I hope I got it
> right). The strange thing is that fill_between() works fine, but
> pan_where() is the problem.
>
> Thanks!
>
> #-------------------------------------------
> import pandas as pd
> import numpy as np
> from datetime import datetime as dt
> import matplotlib.pyplot as plt
> import matplotlib.collections as collections
> span_where = collections.BrokenBarHCollection.span_where
> import matplotlib.units as units
>
> units.registry[np.datetime64] = pd.tseries.converter.DatetimeConverter()
>
> # init the dataframe
> time = pd.date_range(pd.datetime(1950,1,1), periods=5, freq='MS')
> df = pd.DataFrame(np.arange(5), index=time, columns=['data'])
> df['cond'] = df['data'] >= 3
>
> # This is working (but its not what I want)
> x = np.arange(5)
> fig = plt.figure()
> ax = fig.add_subplot(111)
> plt.plot(x, df['data'], 'k')
> c = span_where(x, ymin=0, ymax=4, where=df['cond'], color='green')
> ax.add_collection(c)
> plt.show()
>
> #This is not
> x = df.index.values
> fig = plt.figure()
> ax = fig.add_subplot(111)
> plt.plot(x, df['data'], 'k')
> c = span_where(x, ymin=0, ymax=4, where=df['cond'], color='green')
> ax.add_collection(c)
> plt.show()
>
> #This is producing an error
> x = df.index
> fig = plt.figure()
> ax = fig.add_subplot(111)
> plt.plot(x, df['data'], 'k')
> c = span_where(x, ymin=0, ymax=4, where=df['cond'], color='green')
> ax.add_collection(c)
> plt.show()
> #-------------------------------------------

On 02.12.2014 16:59, Benjamin Root wrote:
> Does the workaround posted here fix things for you?
> https://github.com/matplotlib/matplotlib/issues/3727#issuecomment-60899590
sorry it doesn't.
I updated the test case below (including the workaround, I hope I got it 
right). The strange thing is that fill_between() works fine, but 
pan_where() is the problem.
Thanks!
#-------------------------------------------
import pandas as pd
import numpy as np
from datetime import datetime as dt
import matplotlib.pyplot as plt
import matplotlib.collections as collections
span_where = collections.BrokenBarHCollection.span_where
import matplotlib.units as units
units.registry[np.datetime64] = pd.tseries.converter.DatetimeConverter()
# init the dataframe
time = pd.date_range(pd.datetime(1950,1,1), periods=5, freq='MS')
df = pd.DataFrame(np.arange(5), index=time, columns=['data'])
df['cond'] = df['data'] >= 3
# This is working (but its not what I want)
x = np.arange(5)
fig = plt.figure()
ax = fig.add_subplot(111)
plt.plot(x, df['data'], 'k')
c = span_where(x, ymin=0, ymax=4, where=df['cond'], color='green')
ax.add_collection(c)
plt.show()
#This is not
x = df.index.values
fig = plt.figure()
ax = fig.add_subplot(111)
plt.plot(x, df['data'], 'k')
c = span_where(x, ymin=0, ymax=4, where=df['cond'], color='green')
ax.add_collection(c)
plt.show()
#This is producing an error
x = df.index
fig = plt.figure()
ax = fig.add_subplot(111)
plt.plot(x, df['data'], 'k')
c = span_where(x, ymin=0, ymax=4, where=df['cond'], color='green')
ax.add_collection(c)
plt.show()
#-------------------------------------------

Does the workaround posted here fix things for you?
https://github.com/matplotlib/matplotlib/issues/3727#issuecomment-60899590
On Tue, Dec 2, 2014 at 10:43 AM, Fabien <fab...@gm...> wrote:
> On 02.12.2014 16:34, Benjamin Root wrote:
> > Please provide the full traceback
>
> sure, I pasted the traceback below. Here are the pandas infos:
>
> In [17]: df.info()
> <class 'pandas.core.frame.DataFrame'>
> DatetimeIndex: 5 entries, 1950年01月01日 00:00:00 to 1950年05月01日 00:00:00
> Freq: MS
> Data columns (total 2 columns):
> data 5 non-null int64
> cond 5 non-null bool
> dtypes: bool(1), int64(1)
> memory usage: 85.0 bytes
>
> In [18]: df.index
> Out[18]:
> <class 'pandas.tseries.index.DatetimeIndex'>
> [1950年01月01日, ..., 1950年05月01日]
> Length: 5, Freq: MS, Timezone: None
>
>
> In [19]: df.index.values
> Out[19]:
> array(['1950-01-01T00:00:00.000000000Z', '1950-02-01T00:00:00.000000000Z',
> '1950-03-01T00:00:00.000000000Z', '1950-04-01T00:00:00.000000000Z',
> '1950-05-01T00:00:00.000000000Z'], dtype='datetime64[ns]')
>
>
> Traceback:
>
> In [16]: c = span_where(df.index, ymin=0, ymax=4, where=df['cond'],
> color='green')
> ---------------------------------------------------------------------------
> TypeError Traceback (most recent call last)
> <ipython-input-16-d033044a6db2> in <module>()
> ----> 1 c = span_where(df.index, ymin=0, ymax=4, where=df['cond'],
> color='green')
>
>
> /home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/collections.py
> in span_where(x, ymin, ymax, where, **kwargs)
> 871
> 872 collection = BrokenBarHCollection(
> --> 873 xranges, [ymin, ymax - ymin], **kwargs)
> 874 return collection
> 875
>
>
> /home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/collections.py
> in __init__(self, xranges, yrange, **kwargs)
> 851 (xmin + xwidth, ymin),
> 852 (xmin, ymin)] for xmin, xwidth in xranges]
> --> 853 PolyCollection.__init__(self, verts, **kwargs)
> 854
> 855 @staticmethod
>
>
> /home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/collections.py
> in __init__(self, verts, sizes, closed, **kwargs)
> 799 Collection.__init__(self, **kwargs)
> 800 self.set_sizes(sizes)
> --> 801 self.set_verts(verts, closed)
> 802
> 803 def set_verts(self, verts, closed=True):
>
>
> /home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/collections.py
> in set_verts(self, verts, closed)
> 819 codes[0] = mpath.Path.MOVETO
> 820 codes[-1] = mpath.Path.CLOSEPOLY
> --> 821 self._paths.append(mpath.Path(xy, codes))
> 822 else:
> 823 self._paths.append(mpath.Path(xy))
>
>
> /home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/path.py
> in __init__(self, vertices, codes, _interpolation_steps, closed, readonly)
> 135 vertices = vertices.astype(np.float_).filled(np.nan)
> 136 else:
> --> 137 vertices = np.asarray(vertices, np.float_)
> 138
> 139 if codes is not None:
>
>
> /home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/numpy/core/numeric.py
> in asarray(a, dtype, order)
> 460
> 461 """
> --> 462 return array(a, dtype, copy=False, order=order)
> 463
> 464 def asanyarray(a, dtype=None, order=None):
>
> TypeError: float() argument must be a string or a number
>
>
>
>
>
>
>
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>

On 02.12.2014 16:34, Benjamin Root wrote:
> Please provide the full traceback
sure, I pasted the traceback below. Here are the pandas infos:
In [17]: df.info()
<class 'pandas.core.frame.DataFrame'>
DatetimeIndex: 5 entries, 1950年01月01日 00:00:00 to 1950年05月01日 00:00:00
Freq: MS
Data columns (total 2 columns):
data 5 non-null int64
cond 5 non-null bool
dtypes: bool(1), int64(1)
memory usage: 85.0 bytes
In [18]: df.index
Out[18]:
<class 'pandas.tseries.index.DatetimeIndex'>
[1950年01月01日, ..., 1950年05月01日]
Length: 5, Freq: MS, Timezone: None
In [19]: df.index.values
Out[19]:
array(['1950-01-01T00:00:00.000000000Z', '1950-02-01T00:00:00.000000000Z',
 '1950-03-01T00:00:00.000000000Z', '1950-04-01T00:00:00.000000000Z',
 '1950-05-01T00:00:00.000000000Z'], dtype='datetime64[ns]')
Traceback:
In [16]: c = span_where(df.index, ymin=0, ymax=4, where=df['cond'], 
color='green')
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-16-d033044a6db2> in <module>()
----> 1 c = span_where(df.index, ymin=0, ymax=4, where=df['cond'], 
color='green')
/home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/collections.py 
in span_where(x, ymin, ymax, where, **kwargs)
 871
 872 collection = BrokenBarHCollection(
--> 873 xranges, [ymin, ymax - ymin], **kwargs)
 874 return collection
 875
/home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/collections.py 
in __init__(self, xranges, yrange, **kwargs)
 851 (xmin + xwidth, ymin),
 852 (xmin, ymin)] for xmin, xwidth in xranges]
--> 853 PolyCollection.__init__(self, verts, **kwargs)
 854
 855 @staticmethod
/home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/collections.py 
in __init__(self, verts, sizes, closed, **kwargs)
 799 Collection.__init__(self, **kwargs)
 800 self.set_sizes(sizes)
--> 801 self.set_verts(verts, closed)
 802
 803 def set_verts(self, verts, closed=True):
/home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/collections.py 
in set_verts(self, verts, closed)
 819 codes[0] = mpath.Path.MOVETO
 820 codes[-1] = mpath.Path.CLOSEPOLY
--> 821 self._paths.append(mpath.Path(xy, codes))
 822 else:
 823 self._paths.append(mpath.Path(xy))
/home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/matplotlib/path.py 
in __init__(self, vertices, codes, _interpolation_steps, closed, readonly)
 135 vertices = vertices.astype(np.float_).filled(np.nan)
 136 else:
--> 137 vertices = np.asarray(vertices, np.float_)
 138
 139 if codes is not None:
/home/mowglie/.pyvirtualenvs/py3.3/lib/python3.3/site-packages/numpy/core/numeric.py 
in asarray(a, dtype, order)
 460
 461 """
--> 462 return array(a, dtype, copy=False, order=order)
 463
 464 def asanyarray(a, dtype=None, order=None):
TypeError: float() argument must be a string or a number

You didn't label any of the series that you put on the graph, so the legend
has no idea what to call anything thing.
Like the warning (not error) says, use the label parameter on your calls to
plot, e.g., ax1.plot(..., label='Concentration') or whatever.
Note though, that you're mixing up interfaces in your script as written.
MPL's many interfaces are kind of mess, but you seem reasonably familiar
with the OO interface, so stick to that. What I mean is once you start
messing with ax1, and ax2 directly, don't revert back to call to plt. As
written, you'll only get a legend on ax2, but you haven't plotted anything
there.
If you want a legend on ax1, use ax1.legend.
-p
On Tue, Dec 2, 2014 at 1:59 AM, Tommy Carstensen <tom...@gm...
> wrote:
> In gnuplot it is quite easy to create two axes, but I can't figure out
> how to do it in matplotlib. I'm trying this:
>
> import matplotlib
> matplotlib.use('Agg')
> import matplotlib.pyplot as plt
>
> for key1 in keys1:
> ax1.plot(x, y, style, label=label, color=color, linewidth=3)
> ax1.set_xlabel(xlabel)
> ax1.set_ylabel(ylabel1)
> ax2.set_ylabel(ylabel2)
> plt.legend(loc='lower right', shadow=True)
> plt.suptitle(title, fontsize=14, fontweight='bold')
> axes = plt.gca()
> axes.set_ylim([0,1])
> plt.grid(b=True, which='major', color='k', linestyle='--')
> plt.savefig('{}.png'.format(key1), dpi=600)
> plt.close()
> plt.clf()
>
> But I get this error:
> lib/python3.3/site-packages/matplotlib/axes.py:4749: UserWarning: No
> labeled objects found. Use label='...' kwarg on individual plots.
> warnings.warn("No labeled objects found. "
>
> What am I doing wrong? Thanks.
>
>
> ------------------------------------------------------------------------------
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>

Please provide the full traceback. Could you also show df.info()? In any
case, I suspect that the problem is that pandas recently started using
datetime64 for their timeseries, and matplotlib hasn't implemented the unit
converter for it. There was a post recently showing how to add pandas's
converter to matplotlib's unit framework, but I can't find it right now...
Cheers!
Ben Root
On Tue, Dec 2, 2014 at 9:24 AM, Fabien <fab...@gm...> wrote:
> Folks,
>
> I'm trying to use BrokenBarHCollection with pandas timeseries object.
>
> Here's a minimal example: (python 3.3, pandas 0.15.1, matplotlib 1.4.2)
>
> #-----------------------------------------------------
> import pandas as pd
> import numpy as np
> from datetime import datetime as dt
> import matplotlib.pyplot as plt
> import matplotlib.collections as collections
> span_where = collections.BrokenBarHCollection.span_where
>
> # init the dataframe
> time = pd.date_range(pd.datetime(1950,1,1), periods=5, freq='MS')
> df = pd.DataFrame(np.arange(5), index=time, columns=['data'])
> df['cond'] = df['data'] == 3
>
> # Make the plot
> fig = plt.figure()
> ax = fig.add_subplot(111)
> df['data'].plot(ax=ax, c='black')
> c = span_where(df.index, ymin=0, ymax=4, where=df['cond'],
> facecolor='green', alpha=0.5)
> #-----------------------------------------------------
>
> I get the error:
> "TypeError: float() argument must be a string or a number"
>
> Basically, span_where() is not happy with my x values which are a panda
> timeserie. I tried several stuffs (df.index.to_*) but there is something
> I still don't get in the internal representation of dates in matplolib.
>
> Any hint? Thanks a lot!
>
> Fabien
>
>
>
>
>
>
> ------------------------------------------------------------------------------
> Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server
> from Actuate! Instantly Supercharge Your Business Reports and Dashboards
> with Interactivity, Sharing, Native Excel Exports, App Integration & more
> Get technology previously reserved for billion-dollar corporations, FREE
>
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> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

Folks,
I'm trying to use BrokenBarHCollection with pandas timeseries object.
Here's a minimal example: (python 3.3, pandas 0.15.1, matplotlib 1.4.2)
#-----------------------------------------------------
import pandas as pd
import numpy as np
from datetime import datetime as dt
import matplotlib.pyplot as plt
import matplotlib.collections as collections
span_where = collections.BrokenBarHCollection.span_where
# init the dataframe
time = pd.date_range(pd.datetime(1950,1,1), periods=5, freq='MS')
df = pd.DataFrame(np.arange(5), index=time, columns=['data'])
df['cond'] = df['data'] == 3
# Make the plot
fig = plt.figure()
ax = fig.add_subplot(111)
df['data'].plot(ax=ax, c='black')
c = span_where(df.index, ymin=0, ymax=4, where=df['cond'], 
facecolor='green', alpha=0.5)
#-----------------------------------------------------
I get the error:
"TypeError: float() argument must be a string or a number"
Basically, span_where() is not happy with my x values which are a panda 
timeserie. I tried several stuffs (df.index.to_*) but there is something 
I still don't get in the internal representation of dates in matplolib.
Any hint? Thanks a lot!
Fabien

In gnuplot it is quite easy to create two axes, but I can't figure out
how to do it in matplotlib. I'm trying this:
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
for key1 in keys1:
 ax1.plot(x, y, style, label=label, color=color, linewidth=3)
 ax1.set_xlabel(xlabel)
 ax1.set_ylabel(ylabel1)
 ax2.set_ylabel(ylabel2)
 plt.legend(loc='lower right', shadow=True)
 plt.suptitle(title, fontsize=14, fontweight='bold')
 axes = plt.gca()
 axes.set_ylim([0,1])
 plt.grid(b=True, which='major', color='k', linestyle='--')
 plt.savefig('{}.png'.format(key1), dpi=600)
 plt.close()
 plt.clf()
But I get this error:
lib/python3.3/site-packages/matplotlib/axes.py:4749: UserWarning: No
labeled objects found. Use label='...' kwarg on individual plots.
 warnings.warn("No labeled objects found. "
What am I doing wrong? Thanks.