我在保存一系列两个Seaborn小提琴图和一个普通的matplotlib图时遇到了一些麻烦，每次我的代码遍历一个循环时都会运行。
我的代码是：
for symbol in symbol_list:
<DO SOMETHING - CREATE PANDAS DATAFRAME NAMED "df">
img = sns.violinplot(x=df['Onside'].dropna().astype(float))
fig = img.get_figure()
fig.savefig(symbol+" Onside Violin Plot.png")
fig.clf()
sns.violinplot(x=df['Offside'].dropna().astype(float))
fig = img.get_figure()
fig.savefig(symbol+" Offside Violin Plot.png")
fig.clf()
plt.figure(1)
plt.subplot(211)
plt.hist(df['Onside'],bins=50,alpha=0.5,label="Onside")
plt.hist(df['Offside'],bins=50,alpha=0.5,label="Offside")
plt.legend(loc='best')
plt.xlabel("Pips")
plt.ylabel("Number of Trades")
plt.subplot(212)
plt.bar(df.index,df['Offside'],color='r',width=0.5)
plt.bar(df.index,df['Onside'],color='blue',width=0.5)
plt.savefig(symbol+'_Onside_Offside')
plt.plot()
它在循环的第一次迭代中正确运行但在第二次循环时我收到以下错误消息：
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-51-269b21e53a2f> in <module>()
112 img = sns.violinplot(x=df['Onside'].dropna().astype(float))#.figure.savefig(symbol+" Onside Violin Plot.png")
113 fig = img.get_figure()
--> 114 fig.savefig(symbol+" Onside Violin Plot.png")
115 fig.clf()
116
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\figure.py in savefig(self, *args, **kwargs)
1561 self.set_frameon(frameon)
1562
-> 1563 self.canvas.print_figure(*args, **kwargs)
1564
1565 if frameon:
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\backend_bases.py in print_figure(self, filename, dpi, facecolor, edgecolor, orientation, format, **kwargs)
2230 orientation=orientation,
2231 bbox_inches_restore=_bbox_inches_restore,
-> 2232 **kwargs)
2233 finally:
2234 if bbox_inches and restore_bbox:
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\backends\backend_agg.py in print_png(self, filename_or_obj, *args, **kwargs)
525
526 def print_png(self, filename_or_obj, *args, **kwargs):
--> 527 FigureCanvasAgg.draw(self)
528 renderer = self.get_renderer()
529 original_dpi = renderer.dpi
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\backends\backend_agg.py in draw(self)
472
473 try:
--> 474 self.figure.draw(self.renderer)
475 finally:
476 RendererAgg.lock.release()
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
60 def draw_wrapper(artist, renderer, *args, **kwargs):
61 before(artist, renderer)
---> 62 draw(artist, renderer, *args, **kwargs)
63 after(artist, renderer)
64
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\figure.py in draw(self, renderer)
1157 dsu.sort(key=itemgetter(0))
1158 for zorder, a, func, args in dsu:
-> 1159 func(*args)
1160
1161 renderer.close_group('figure')
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
60 def draw_wrapper(artist, renderer, *args, **kwargs):
61 before(artist, renderer)
---> 62 draw(artist, renderer, *args, **kwargs)
63 after(artist, renderer)
64
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axes\_base.py in draw(self, renderer, inframe)
2317
2318 for zorder, a in dsu:
-> 2319 a.draw(renderer)
2320
2321 renderer.close_group('axes')
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
60 def draw_wrapper(artist, renderer, *args, **kwargs):
61 before(artist, renderer)
---> 62 draw(artist, renderer, *args, **kwargs)
63 after(artist, renderer)
64
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axis.py in draw(self, renderer, *args, **kwargs)
1106 renderer.open_group(__name__)
1107
-> 1108 ticks_to_draw = self._update_ticks(renderer)
1109 ticklabelBoxes, ticklabelBoxes2 = self._get_tick_bboxes(ticks_to_draw,
1110 renderer)
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axis.py in _update_ticks(self, renderer)
949
950 interval = self.get_view_interval()
--> 951 tick_tups = [t for t in self.iter_ticks()]
952 if self._smart_bounds:
953 # handle inverted limits
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axis.py in <listcomp>(.0)
949
950 interval = self.get_view_interval()
--> 951 tick_tups = [t for t in self.iter_ticks()]
952 if self._smart_bounds:
953 # handle inverted limits
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axis.py in iter_ticks(self)
892 Iterate through all of the major and minor ticks.
893 """
--> 894 majorLocs = self.major.locator()
895 majorTicks = self.get_major_ticks(len(majorLocs))
896 self.major.formatter.set_locs(majorLocs)
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in __call__(self)
1005 def __call__(self):
1006 'Return the locations of the ticks'
-> 1007 self.refresh()
1008 return self._locator()
1009
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in refresh(self)
1025 def refresh(self):
1026 'Refresh internal information based on current limits.'
-> 1027 dmin, dmax = self.viewlim_to_dt()
1028 self._locator = self.get_locator(dmin, dmax)
1029
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in viewlim_to_dt(self)
769 vmin, vmax = vmax, vmin
770
--> 771 return num2date(vmin, self.tz), num2date(vmax, self.tz)
772
773 def _get_unit(self):
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in num2date(x, tz)
417 tz = _get_rc_timezone()
418 if not cbook.iterable(x):
--> 419 return _from_ordinalf(x, tz)
420 else:
421 x = np.asarray(x)
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in _from_ordinalf(x, tz)
269
270 ix = int(x)
--> 271 dt = datetime.datetime.fromordinal(ix).replace(tzinfo=UTC)
272
273 remainder = float(x) - ix
ValueError: ordinal must be >= 1
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\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:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\IPython\core\pylabtools.py in <lambda>(fig)
225
226 if 'png' in formats:
--> 227 png_formatter.for_type(Figure, lambda fig: print_figure(fig, 'png', **kwargs))
228 if 'retina' in formats or 'png2x' in formats:
229 png_formatter.for_type(Figure, lambda fig: retina_figure(fig, **kwargs))
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\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:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\backend_bases.py in print_figure(self, filename, dpi, facecolor, edgecolor, orientation, format, **kwargs)
2178 orientation=orientation,
2179 dryrun=True,
-> 2180 **kwargs)
2181 renderer = self.figure._cachedRenderer
2182 bbox_inches = self.figure.get_tightbbox(renderer)
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\backends\backend_agg.py in print_png(self, filename_or_obj, *args, **kwargs)
525
526 def print_png(self, filename_or_obj, *args, **kwargs):
--> 527 FigureCanvasAgg.draw(self)
528 renderer = self.get_renderer()
529 original_dpi = renderer.dpi
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\backends\backend_agg.py in draw(self)
472
473 try:
--> 474 self.figure.draw(self.renderer)
475 finally:
476 RendererAgg.lock.release()
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
60 def draw_wrapper(artist, renderer, *args, **kwargs):
61 before(artist, renderer)
---> 62 draw(artist, renderer, *args, **kwargs)
63 after(artist, renderer)
64
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\figure.py in draw(self, renderer)
1157 dsu.sort(key=itemgetter(0))
1158 for zorder, a, func, args in dsu:
-> 1159 func(*args)
1160
1161 renderer.close_group('figure')
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
60 def draw_wrapper(artist, renderer, *args, **kwargs):
61 before(artist, renderer)
---> 62 draw(artist, renderer, *args, **kwargs)
63 after(artist, renderer)
64
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axes\_base.py in draw(self, renderer, inframe)
2317
2318 for zorder, a in dsu:
-> 2319 a.draw(renderer)
2320
2321 renderer.close_group('axes')
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
60 def draw_wrapper(artist, renderer, *args, **kwargs):
61 before(artist, renderer)
---> 62 draw(artist, renderer, *args, **kwargs)
63 after(artist, renderer)
64
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axis.py in draw(self, renderer, *args, **kwargs)
1106 renderer.open_group(__name__)
1107
-> 1108 ticks_to_draw = self._update_ticks(renderer)
1109 ticklabelBoxes, ticklabelBoxes2 = self._get_tick_bboxes(ticks_to_draw,
1110 renderer)
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axis.py in _update_ticks(self, renderer)
949
950 interval = self.get_view_interval()
--> 951 tick_tups = [t for t in self.iter_ticks()]
952 if self._smart_bounds:
953 # handle inverted limits
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axis.py in <listcomp>(.0)
949
950 interval = self.get_view_interval()
--> 951 tick_tups = [t for t in self.iter_ticks()]
952 if self._smart_bounds:
953 # handle inverted limits
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\axis.py in iter_ticks(self)
892 Iterate through all of the major and minor ticks.
893 """
--> 894 majorLocs = self.major.locator()
895 majorTicks = self.get_major_ticks(len(majorLocs))
896 self.major.formatter.set_locs(majorLocs)
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in __call__(self)
1005 def __call__(self):
1006 'Return the locations of the ticks'
-> 1007 self.refresh()
1008 return self._locator()
1009
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in refresh(self)
1025 def refresh(self):
1026 'Refresh internal information based on current limits.'
-> 1027 dmin, dmax = self.viewlim_to_dt()
1028 self._locator = self.get_locator(dmin, dmax)
1029
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in viewlim_to_dt(self)
769 vmin, vmax = vmax, vmin
770
--> 771 return num2date(vmin, self.tz), num2date(vmax, self.tz)
772
773 def _get_unit(self):
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in num2date(x, tz)
417 tz = _get_rc_timezone()
418 if not cbook.iterable(x):
--> 419 return _from_ordinalf(x, tz)
420 else:
421 x = np.asarray(x)
C:\Users\stuart.jamieson\AppData\Local\Continuum\Anaconda3\lib\site-packages\matplotlib\dates.py in _from_ordinalf(x, tz)
269
270 ix = int(x)
--> 271 dt = datetime.datetime.fromordinal(ix).replace(tzinfo=UTC)
272
273 remainder = float(x) - ix
ValueError: ordinal must be >= 1
有人可以指出我哪里出错吗？
我认为这与“plt”数字没有被正确清除有关，因此代码试图在同一图的x轴上绘制两个不同的索引，因此“序数必须> = 1”错误。
我在正确的球场吗？
答案 0 :(得分：1)
你需要在循环中首先清除图形，否则新内容将绘制到上一循环步骤中的旧图形。
所以你可以添加
plt.gcf().clf()
在循环开始时。