Thank you for the immediate and extremely helpful suggestions.  Changing the string to a tuple works great, and I did not think about using the "label" keyword in plot.  I think this will greatly simplify the plotting.

Thanks again for the "instant gratification".  :)


Charles

==========

The 2nd Law of Thermodynamics... If you think things are a mess now, JUST WAIT!


On Tue, Sep 16, 2008 at 3:28 PM, Jae-Joon Lee <lee.j.joon@gmail.com> wrote:
('CO2') is not a tuple but still a single string.
You may use a list  ['CO2'] or put an extra "," to make it a tuple ('CO2',).

And, you may consider to use the "label" keyword with your plot command.
IHTH,

-JJ



On Tue, Sep 16, 2008 at 5:09 PM, charles reid <charlesreid1@gmail.com> wrote:
> Hi there -
>
> I'm using the latest stable pylab/matplotlib (0.98.3) via OS X 10.5.4.  I am
> plotting a simple array of data, and I'm getting some strange behavior when
> I try to add a legend to the plot.
> First, the plot without the legend:
>
> f=figure(1)
> title("Equilibrium Concentration vs. Equivalence Ratio")
> line1 = plot(phi,xeq[1])
> show()
>
> This works fine.  However, when I try to add a legend, I get an error.  I
> add this:
>
> f=figure(1)
> title("Equilibrium Concentration vs. Equivalence Ratio")
> line1 = plot(phi,xeq[1])
> f.legend(line1,('CO2'),loc=(0.8,0.8))
> show()
>
> And it gives me an error because of the second argument to f.legend:
>
> ---------------------------------------------------------------------------
> ValueError                                Traceback (most recent call last)
>
> /Users/charles/Documents/school/combustion/problem-2-52/adiabatic.py in
> <module>()
>     111 title("Equilibrium Concentrations vs. Equivalence Ratio")
>     112 line1=plot(phi,xeq[1])
> --> 113 f.legend(line1,('CO2'),loc=(0.8,0.8))
>     114 show()
>     115
>
> /Library/Python/2.5/site-packages/matplotlib-0.98.3-py2.5-macosx-10.3-i386.egg/matplotlib/figure.pyc
> in legend(self, handles, labels, *args, **kwargs)
>     841         """
>     842         handles = flatten(handles)
> --> 843         l = Legend(self, handles, labels, *args, **kwargs)
>     844         self.legends.append(l)
>     845         return l
>
> /Library/Python/2.5/site-packages/matplotlib-0.98.3-py2.5-macosx-10.3-i386.egg/matplotlib/legend.pyc
> in __init__(self, parent, handles, labels, loc, numpoints, prop, pad,
> markerscale, labelsep, handlelen, handletextsep, axespad, shadow)
>     180         textleft = left+ self.handlelen+self.handletextsep
>     181         self.texts = self._get_texts(labels, textleft, top)
> --> 182         self.legendHandles = self._get_handles(handles, self.texts)
>     183
>     184         self._drawFrame = True
>
> /Library/Python/2.5/site-packages/matplotlib-0.98.3-py2.5-macosx-10.3-i386.egg/matplotlib/legend.pyc
> in _get_handles(self, handles, texts)
>     246         # centered marker proxy
>     247
> --> 248         for handle, label in safezip(handles, texts):
>     249             if self.numpoints > 1:
>     250                 xdata = np.linspace(left, left + self.handlelen,
> self.numpoints)
>
> /Library/Python/2.5/site-packages/matplotlib-0.98.3-py2.5-macosx-10.3-i386.egg/matplotlib/cbook.pyc
> in safezip(*args)
>     899     for i, arg in enumerate(args[1:]):
>     900         if len(arg) != Nx:
> --> 901             raise ValueError(_safezip_msg % (Nx, i+1, len(arg)))
>     902     return zip(*args)
>     903
>
> ValueError: In safezip, len(args[0])=1 but len(args[1])=3
> WARNING: Failure executing file: <adiabatic.py>
>
> I don't understand why this doesn't work, because I should be able to give a
> label of arbitrary length.  It doesn't work when I replace single quotes
> with double quotes, either.  But I change the length to 1, like it wants:
>
> f=figure(1)
> title("Equilibrium Concentrations vs. Equivalence Ratio")
> line1=plot(phi,xeq[1])
> f.legend(line1,('C'),loc=(0.8,0.8))
> show()
>
> Which creates a plot, with a legend, but when I move the mouse over the
> plot, it has the "thinking" cursor (hourglass).   I can't close the window
> using the buttons in the upper left hand corner, I can't close it using
> close(1), and I can't close it using close('all').  I end up having to run
> 'killall Python' from a command line.
>
> I can get the plot with the legend to work, albeit with only ONE character
> for the name, by running (from Python)
>
> f=figure(1)
> title("Equilibrium Concentrations vs. Equivalence Ratio")
> line1=plot(phi,xeq[1])
> f.legend(line1,('C'),loc=(0.8,0.8))
>
> (without the show() command) in the script, then running show() when the
> script is done, and I don't get the "thinking" cursor.
>
> Note: I have also used the function figlegend() with the exact same
> results/problems.
>
> 1. How can I give a legend name with a length of more than 1 character?
> What am I doing wrong?
> 2. What is causing the behavior with the thinking cursor?
>
>
> Also, ultimately I would like to make a plot with 30+ species, instead of
> just CO2.  Is there a way to do this other than doing the following?
>
> line1 line2 line3 ........ =
> plot(phi,xeq[1],phi,xeq[2],phi,xeq[3],...........)
> f.legend((line1,line2,...........),(name[0],name[1],name[2],................),loc=(0.8,0.8))
>
> Thanks ahead of time for any suggestions or hints.
>
>
>
> Charles
>
>
>
>
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