参考 这个答案中的DateFormatter用法，我尝试使用pandas 0.15.0和matplotlib 1.4.2绘制时间序列并将x轴标签设置为年份:
import datetime as dt
import matplotlib as mpl
import matplotlib.pyplot as plt
import pandas.io.data as pdio
import scipy as sp
t1 = dt.datetime(1960, 1, 1)
t2 = dt.datetime(2014, 6, 1)
data = pdio.DataReader("GS10", "fred", t1, t2).resample("Q", how=sp.mean)
fig, ax1 = plt.subplots()
ax1.plot(data.index, data.GS10)
ax1.set_xlabel("Year")
ax1.set_ylabel("Rate (%)")
ax1.xaxis.set_major_formatter(mpl.dates.DateFormatter("%Y"))
fig.suptitle("10-yr Treasury Rate", fontsize=14)
fig.savefig('test.eps')
最后一行抛出了一个错误：
OverflowError: Python int太大，无法转换为C long，并附带以下追踪信息：C:\Anaconda3\lib\site-packages\IPython\core\formatters.py:239: FormatterWarning: Exception in image/png formatter: Python int too large to convert to C long FormatterWarning, Traceback (most recent call last): File "", line 1, in runfile('D:/username/latex_template/new_pandas_example.py', wdir='D:/username/latex_template') File "C:\Anaconda3\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 580, in runfile execfile(filename, namespace) File "C:\Anaconda3\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 48, in execfile exec(compile(open(filename, 'rb').read(), filename, 'exec'), namespace) File "D:/username/latex_template/new_pandas_example.py", line 18, in fig.savefig('test.eps') File "C:\Anaconda3\lib\site-packages\matplotlib\figure.py", line 1470, in savefig self.canvas.print_figure(*args, **kwargs) File "C:\Anaconda3\lib\site-packages\matplotlib\backend_bases.py", line 2194, in print_figure **kwargs) File "C:\Anaconda3\lib\site-packages\matplotlib\backends\backend_ps.py", line 992, in print_eps return self._print_ps(outfile, 'eps', *args, **kwargs) File "C:\Anaconda3\lib\site-packages\matplotlib\backends\backend_ps.py", line 1020, in _print_ps **kwargs) File "C:\Anaconda3\lib\site-packages\matplotlib\backends\backend_ps.py", line 1110, in _print_figure self.figure.draw(renderer) File "C:\Anaconda3\lib\site-packages\matplotlib\artist.py", line 59, in draw_wrapper draw(artist, renderer, *args, **kwargs) File "C:\Anaconda3\lib\site-packages\matplotlib\figure.py", line 1079, in draw func(*args) File "C:\Anaconda3\lib\site-packages\matplotlib\artist.py", line 59, in draw_wrapper draw(artist, renderer, *args, **kwargs) File "C:\Anaconda3\lib\site-packages\matplotlib\axes_base.py", line 2092, in draw a.draw(renderer) File "C:\Anaconda3\lib\site-packages\matplotlib\artist.py", line 59, in draw_wrapper draw(artist, renderer, *args, **kwargs) File "C:\Anaconda3\lib\site-packages\matplotlib\axis.py", line 1114, in draw ticks_to_draw = self._update_ticks(renderer) File "C:\Anaconda3\lib\site-packages\matplotlib\axis.py", line 957, in _update_ticks tick_tups = [t for t in self.iter_ticks()] File "C:\Anaconda3\lib\site-packages\matplotlib\axis.py", line 957, in tick_tups = [t for t in self.iter_ticks()] File "C:\Anaconda3\lib\site-packages\matplotlib\axis.py", line 905, in iter_ticks for i, val in enumerate(majorLocs)] File "C:\Anaconda3\lib\site-packages\matplotlib\axis.py", line 905, in for i, val in enumerate(majorLocs)] File "C:\Anaconda3\lib\site-packages\matplotlib\dates.py", line 411, in call dt = num2date(x, self.tz) File "C:\Anaconda3\lib\site-packages\matplotlib\dates.py", line 345, in num2date return _from_ordinalf(x, tz) File "C:\Anaconda3\lib\site-packages\matplotlib\dates.py", line 225, in _from_ordinalf dt = datetime.datetime.fromordinal(ix) OverflowError: Python int too large to convert to C long
我在这里使用 DateFormatter 是否有误？如何轻松地将年份（或任何时间格式，因为我的时间序列可能不同）放在 matplotlib 图形的 x 轴上？