为什么会出现错误"OverflowError:Python int太大而无法转换为C long"?来自pandas/matplotlib吗? [英] Why am I getting the error "OverflowError: Python int too large to convert to C long" from pandas/matplotlib?

问题描述

我有一个熊猫数据框，其中包含日期和最大值和最小值，称为solflux:

I have a pandas dataframe with dates and maximum and minimum values called solflux:

    date        max   min
0   2015-01-01  148  10.5
1   2015-02-01  142   9.5
2   2015-03-01  140   9.0
3   2015-04-01  135   7.5
4   2015-05-01  132   7.5
...

我想将这些值绘制为matplotlib中的错误栏.我使用以下内容查找所需的值

I want to plot these values as errorbars in matplotlib. I use the following to find the values I want

dates = solflux['date']
deltas = (solflux['max'] - solflux['min'])/2
means = solflux['min'] + deltas

然后用

import matplotlib.pyplot as plt
f = plt.figure()
ax = f.add_subplot(111)
ax.errorbar(dates, means, marker='+', yerr=deltas)

然后我得到这个错误:

C:\Anaconda3\lib\site-packages\matplotlib\axes\_axes.py:545: UserWarning: No labelled objects found. Use label='...' kwarg on individu
al plots.
  warnings.warn("No labelled objects found. "
Traceback (most recent call last):
  File "C:\Anaconda3\lib\site-packages\matplotlib\backends\backend_qt5agg.py", line 197, in __draw_idle_agg
    FigureCanvasAgg.draw(self)
  File "C:\Anaconda3\lib\site-packages\matplotlib\backends\backend_agg.py", line 464, in draw
    self.figure.draw(self.renderer)
  File "C:\Anaconda3\lib\site-packages\matplotlib\artist.py", line 63, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "C:\Anaconda3\lib\site-packages\matplotlib\figure.py", line 1143, in draw
    renderer, self, dsu, self.suppressComposite)
  File "C:\Anaconda3\lib\site-packages\matplotlib\image.py", line 139, in _draw_list_compositing_images
    a.draw(renderer)
  File "C:\Anaconda3\lib\site-packages\matplotlib\artist.py", line 63, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "C:\Anaconda3\lib\site-packages\matplotlib\axes\_base.py", line 2409, in draw
    mimage._draw_list_compositing_images(renderer, self, dsu)
  File "C:\Anaconda3\lib\site-packages\matplotlib\image.py", line 139, in _draw_list_compositing_images
    a.draw(renderer)
  File "C:\Anaconda3\lib\site-packages\matplotlib\artist.py", line 63, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "C:\Anaconda3\lib\site-packages\matplotlib\axis.py", line 1136, in draw
    ticks_to_draw = self._update_ticks(renderer)
  File "C:\Anaconda3\lib\site-packages\matplotlib\axis.py", line 969, in _update_ticks
    tick_tups = [t for t in self.iter_ticks()]
  File "C:\Anaconda3\lib\site-packages\matplotlib\axis.py", line 969, in <listcomp>
    tick_tups = [t for t in self.iter_ticks()]
  File "C:\Anaconda3\lib\site-packages\matplotlib\axis.py", line 912, in iter_ticks
    majorLocs = self.major.locator()
  File "C:\Anaconda3\lib\site-packages\matplotlib\dates.py", line 983, in __call__
    self.refresh()
  File "C:\Anaconda3\lib\site-packages\matplotlib\dates.py", line 1003, in refresh
    dmin, dmax = self.viewlim_to_dt()
  File "C:\Anaconda3\lib\site-packages\matplotlib\dates.py", line 760, in viewlim_to_dt
    return num2date(vmin, self.tz), num2date(vmax, self.tz)
  File "C:\Anaconda3\lib\site-packages\matplotlib\dates.py", line 401, in num2date
    return _from_ordinalf(x, tz)
  File "C:\Anaconda3\lib\site-packages\matplotlib\dates.py", line 254, in _from_ordinalf
    dt = datetime.datetime.fromordinal(ix).replace(tzinfo=UTC)
OverflowError: Python int too large to convert to C long

奇怪的是，如果我忽略yerr部分而只是运行

The strange thing is that if I ignore the yerr part and just run

ax.plot(dates, means, marker='+')

一切正常.我怀疑这是matplotlib中的错误，但想知道是否有人提出建议?

everything works as expected. I suspect this is a bug in matplotlib, but was wondering if anyone had any suggestions?

我正在运行Python 3.6.0，Matplotlib 2.0.0和Pandas 0.19.2，据我所知，这些都是最新的.

I'm running Python 3.6.0, Matplotlib 2.0.0 and Pandas 0.19.2 which is all up to date as far as I am aware.

推荐答案

当我尝试运行您的示例代码时，我也遇到了一个错误，但它与您发布的代码不同.我看到的错误是:

I also got an error when I tried to run your example code, but it wasn't the same one you posted. The error I see is:

ValueError: invalid literal for float(): 2015-01-01

不过，您发布的错误跟踪也似乎与日期转换有关，因此我们可能会处理基本上相同的问题-您是否将日期存储为日期对象?使用

The error trace you posted also seems to be concerned with date conversions, though, so we may be dealing with basically the same problem - are you dates stored as date objects? I'm able to run your example code successfully after explicitly converting dates to a Datetime object, using to_datetime():

    date        max   min
0   2015-01-01  148  10.5
1   2015-02-01  142   9.5
2   2015-03-01  140   9.0
3   2015-04-01  135   7.5
4   2015-05-01  132   7.5

solflux = pd.read_clipboard()
dates = pd.to_datetime(solflux['date'])
deltas = (solflux['max'] - solflux['min'])/2
means = solflux['min'] + deltas

f = plt.figure()
ax = f.add_subplot(111)
ax.errorbar(dates, means, marker='+', yerr=deltas)

但是，请注意，您可以使用本机Pandas功能获得相同的结果，并且刻度标签最终会变得更加整洁:

Note, however, that you can achieve the same result using native Pandas functionality, and the tick labels end up a bit neater this way:

solflux.date = pd.to_datetime(solflux.date)
solflux['deltas'] = (solflux['max'] - solflux['min'])/2
solflux['means'] = solflux['min'] + solflux.deltas

数据框:

        date  max   min  deltas  means
0 2015-01-01  148  10.5   68.75  79.25
1 2015-02-01  142   9.5   66.25  75.75
2 2015-03-01  140   9.0   65.50  74.50
3 2015-04-01  135   7.5   63.75  71.25
4 2015-05-01  132   7.5   62.25  69.75

现在使用plot()(可以选择将date设置为索引，也可以只在plot()内设置x='date'):

Now use plot() (optionally set date as index, you can also just set x='date' inside plot()):

solflux.set_index('date').plot(y='means', yerr='deltas', legend=False)

这篇关于为什么会出现错误"OverflowError:Python int太大而无法转换为C long"?来自pandas/matplotlib吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！