Stacked Bar Chart Question in matplotlib 1.0.0

Sean_Lake · March 23, 2011, 1:43pm

Hello all,

I need to draw different hatch styles on the different groups of a stacked bar chart in order to make a figure that works properly in black and white. The devil is, I can't figure out how to do it. When I pass the hatch option a list of values, I get an error.

A simple example:
from numpy import *
import matplotlib.pyplot as plt

plt.hist( [ linspace(1, 10, 20), linspace(1, 10, 40)], bins=range(10), histtype="barstacked", rwidth=1.0, label=["a", "b"],
color=["red", "green"], hatch=["/", "x"] )
plt.show()

The resulting errors/outputs are at the end of the email.

Thanks in advance for any help,
Sean Lake

In [4]: plt.hist( [ linspace(1, 10, 20), linspace(1, 10, 40)], bins=range(10), histtype
="barstacked", rwidth=1.0, label=["a", "b"],
...: color=["red", "green"], hatch=["/", "x"] )
Out[4]:
([array([0, 3, 2, 2, 2, 2, 2, 2, 2]), array([0, 5, 4, 4, 5, 4, 4, 5, 4])],
array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]),
<a list of 2 Lists of Patches objects>)

In [5]: plt.show()

···

---------------------------------------------------------------------------
TypeError Traceback (most recent call last)

/sw/lib/python2.6/site-packages/matplotlib/backends/backend_gtk.pyc in expose_event(self, widget, event)
    391 x, y, w, h = self.allocation
    392 self._pixmap_prepare (w, h)
--> 393 self._render_figure(self._pixmap, w, h)
    394 self._need_redraw = False
    395

/sw/lib/python2.6/site-packages/matplotlib/backends/backend_gtkagg.pyc in _render_figure(self, pixmap, width, height)
     73 def _render_figure(self, pixmap, width, height):
     74 if DEBUG: print 'FigureCanvasGTKAgg.render_figure'
---> 75 FigureCanvasAgg.draw(self)
     76 if DEBUG: print 'FigureCanvasGTKAgg.render_figure pixmap', pixmap
     77 #agg_to_gtk_drawable(pixmap, self.renderer._renderer, None)

/sw/lib/python2.6/site-packages/matplotlib/backends/backend_agg.pyc in draw(self)
    392
    393 self.renderer = self.get_renderer()
--> 394 self.figure.draw(self.renderer)
    395
    396 def get_renderer(self):

/sw/lib/python2.6/site-packages/matplotlib/artist.pyc in draw_wrapper(artist, renderer, *args, **kwargs)
     53 def draw_wrapper(artist, renderer, *args, **kwargs):
     54 before(artist, renderer)
---> 55 draw(artist, renderer, *args, **kwargs)
     56 after(artist, renderer)
     57

/sw/lib/python2.6/site-packages/matplotlib/figure.pyc in draw(self, renderer)
    796 dsu.sort(key=itemgetter(0))
    797 for zorder, func, args in dsu:
--> 798 func(*args)
    799
    800 renderer.close_group('figure')

/sw/lib/python2.6/site-packages/matplotlib/artist.pyc in draw_wrapper(artist, renderer, *args, **kwargs)
     53 def draw_wrapper(artist, renderer, *args, **kwargs):
     54 before(artist, renderer)
---> 55 draw(artist, renderer, *args, **kwargs)
     56 after(artist, renderer)
     57

/sw/lib/python2.6/site-packages/matplotlib/axes.pyc in draw(self, renderer, inframe)
   1932
   1933 for zorder, a in dsu:
-> 1934 a.draw(renderer)
   1935
   1936 renderer.close_group('axes')

/sw/lib/python2.6/site-packages/matplotlib/artist.pyc in draw_wrapper(artist, renderer, *args, **kwargs)
     53 def draw_wrapper(artist, renderer, *args, **kwargs):
     54 before(artist, renderer)
---> 55 draw(artist, renderer, *args, **kwargs)
     56 after(artist, renderer)
     57

/sw/lib/python2.6/site-packages/matplotlib/patches.pyc in draw(self, renderer)
    381 path_effect.draw_path(renderer, gc, tpath, affine, rgbFace)
    382 else:
--> 383 renderer.draw_path(gc, tpath, affine, rgbFace)
    384
    385 gc.restore()

/sw/lib/python2.6/site-packages/matplotlib/backends/backend_agg.pyc in draw_path(self, gc, path, transform, rgbFace)
    115 self._renderer.draw_path(gc, p, transform, rgbFace)
    116 else:
--> 117 self._renderer.draw_path(gc, path, transform, rgbFace)
    118
    119 def draw_mathtext(self, gc, x, y, s, prop, angle):

/sw/lib/python2.6/site-packages/matplotlib/backend_bases.pyc in get_hatch_path(self, density)
    865 if self._hatch is None:
    866 return None
--> 867 return Path.hatch(self._hatch, density)
    868
    869

/sw/lib/python2.6/site-packages/matplotlib/path.pyc in hatch(cls, hatchpattern, density)
    662 return None
    663
--> 664 hatch_path = cls._hatch_dict.get((hatchpattern, density))
    665 if hatch_path is not None:
    666 return hatch_path

TypeError: unhashable type: 'list'
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)