我想从数据框绘制线图，每列一行（列数不同）。 e.g。
In:
import pandas as pd
import matplotlib.pyplot as plt
df=pd.DataFrame (index = range (1,6),columns=['a','b'])
df['a'] = [1,1,1,1,1]
df['b']=[5,5,5,5,5]
df
Out:
a b
1 1 5
2 1 5
3 1 5
4 1 5
5 1 5
我正在使用subplots，因为我想将其他图添加到相同的轴，颜色相同。我发送了.plot一份颜色列表：
fig,ax=plt.subplots()
colours = ['r', 'b','g','y','m','c'][0:len(df.columns)]
ax.plot(df,linestyle = '-',color=colours)
plt.show()
我收到ValueError: Invalid RGBA argument: ['r','b']个例外。完整的错误消息是：
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\colors.py in to_rgba(c, alpha)
154 try:
--> 155 rgba = _colors_full_map.cache[c, alpha]
156 except (KeyError, TypeError): # Not in cache, or unhashable.
TypeError: unhashable type: 'list'
During handling of the above exception, another exception occurred:
ValueError Traceback (most recent call last)
C:\PYTHONprojects\venv\lib\site-packages\IPython\core\formatters.py in __call__(self, obj)
305 pass
306 else:
--> 307 return printer(obj)
308 # Finally look for special method names
309 method = get_real_method(obj, self.print_method)
C:\PYTHONprojects\venv\lib\site-packages\IPython\core\pylabtools.py in <lambda>(fig)
226
227 if 'png' in formats:
--> 228 png_formatter.for_type(Figure, lambda fig: print_figure(fig, 'png', **kwargs))
229 if 'retina' in formats or 'png2x' in formats:
230 png_formatter.for_type(Figure, lambda fig: retina_figure(fig, **kwargs))
C:\PYTHONprojects\venv\lib\site-packages\IPython\core\pylabtools.py in print_figure(fig, fmt, bbox_inches, **kwargs)
117
118 bytes_io = BytesIO()
--> 119 fig.canvas.print_figure(bytes_io, **kw)
120 data = bytes_io.getvalue()
121 if fmt == 'svg':
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\backend_bases.py in print_figure(self, filename, dpi, facecolor, edgecolor, orientation, format, **kwargs)
2208 orientation=orientation,
2209 dryrun=True,
-> 2210 **kwargs)
2211 renderer = self.figure._cachedRenderer
2212 bbox_inches = self.figure.get_tightbbox(renderer)
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\backends\backend_agg.py in print_png(self, filename_or_obj, *args, **kwargs)
509
510 def print_png(self, filename_or_obj, *args, **kwargs):
--> 511 FigureCanvasAgg.draw(self)
512 renderer = self.get_renderer()
513 original_dpi = renderer.dpi
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\backends\backend_agg.py in draw(self)
429 # if toolbar:
430 # toolbar.set_cursor(cursors.WAIT)
--> 431 self.figure.draw(self.renderer)
432 # A GUI class may be need to update a window using this draw, so
433 # don't forget to call the superclass.
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
53 renderer.start_filter()
54
---> 55 return draw(artist, renderer, *args, **kwargs)
56 finally:
57 if artist.get_agg_filter() is not None:
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\figure.py in draw(self, renderer)
1473
1474 mimage._draw_list_compositing_images(
-> 1475 renderer, self, artists, self.suppressComposite)
1476
1477 renderer.close_group('figure')
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\image.py in _draw_list_compositing_images(renderer, parent, artists, suppress_composite)
139 if not_composite or not has_images:
140 for a in artists:
--> 141 a.draw(renderer)
142 else:
143 # Composite any adjacent images together
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
53 renderer.start_filter()
54
---> 55 return draw(artist, renderer, *args, **kwargs)
56 finally:
57 if artist.get_agg_filter() is not None:
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\axes\_base.py in draw(self, renderer, inframe)
2605 renderer.stop_rasterizing()
2606
-> 2607 mimage._draw_list_compositing_images(renderer, self, artists)
2608
2609 renderer.close_group('axes')
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\image.py in _draw_list_compositing_images(renderer, parent, artists, suppress_composite)
139 if not_composite or not has_images:
140 for a in artists:
--> 141 a.draw(renderer)
142 else:
143 # Composite any adjacent images together
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
53 renderer.start_filter()
54
---> 55 return draw(artist, renderer, *args, **kwargs)
56 finally:
57 if artist.get_agg_filter() is not None:
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\lines.py in draw(self, renderer)
759 self._set_gc_clip(gc)
760
--> 761 ln_color_rgba = self._get_rgba_ln_color()
762 gc.set_foreground(ln_color_rgba, isRGBA=True)
763 gc.set_alpha(ln_color_rgba[3])
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\lines.py in _get_rgba_ln_color(self, alt)
1260
1261 def _get_rgba_ln_color(self, alt=False):
-> 1262 return mcolors.to_rgba(self._color, self._alpha)
1263
1264 # some aliases....
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\colors.py in to_rgba(c, alpha)
155 rgba = _colors_full_map.cache[c, alpha]
156 except (KeyError, TypeError): # Not in cache, or unhashable.
--> 157 rgba = _to_rgba_no_colorcycle(c, alpha)
158 try:
159 _colors_full_map.cache[c, alpha] = rgba
C:\PYTHONprojects\venv\lib\site-packages\matplotlib\colors.py in _to_rgba_no_colorcycle(c, alpha)
206 # float)` and `np.array(...).astype(float)` all convert "0.5" to 0.5.
207 # Test dimensionality to reject single floats.
--> 208 raise ValueError("Invalid RGBA argument: {!r}".format(orig_c))
209 # Return a tuple to prevent the cached value from being modified.
210 c = tuple(c.astype(float))
ValueError: Invalid RGBA argument: ['r', 'b']
<Figure size 432x288 with 1 Axes>
我做错了什么？我应该如何传递颜色列表，每列一个？
答案 0 :(得分：1)
matplotlib的plot函数不接受这样的颜色列表。但是，如果使用方法DataFrame.plot，则可以指定颜色。
df.plot(linestyle='-', color=colours, ax=ax)