项目场景：

        通过Backtrader框架对tushare获取的股票数据做回测调用cerebro.plot()时报错：        

        ImportError：cannot import name ‘warnings’

问题描述

详细报错信息如下：

Traceback (most recent call last):
  File "D:\Anaconda3\lib\tkinter\__init__.py", line 1702, in __call__
    return self.func(*args)
  File "D:\Desktop\新建文件夹 (2)\cfc-validation\SimTrade\gui_simtrade.py", line 338, in execOpTradebackDay
    cerebro.plot()
  File "D:\Anaconda3\lib\site-packages\backtrader\cerebro.py", line 974, in plot
    from . import plot
  File "D:\Anaconda3\lib\site-packages\backtrader\plot\__init__.py", line 43, in <module>
    from .plot import Plot, Plot_OldSync
  File "D:\Anaconda3\lib\site-packages\backtrader\plot\plot.py", line 44, in <module>
    from . import locator as loc
  File "D:\Anaconda3\lib\site-packages\backtrader\plot\locator.py", line 35, in <module>
    from matplotlib.dates import (HOURS_PER_DAY, MIN_PER_HOUR, SEC_PER_MIN,
ImportError: cannot import name 'warnings'

原因分析：

认真看这里的报错信息，定位到

D:\Anaconda3\lib\site-packages\backtrader\plot\locator.py

from matplotlib.dates import (HOURS_PER_DAY, MIN_PER_HOUR, SEC_PER_MIN,
                              MONTHS_PER_YEAR, DAYS_PER_WEEK,
                              SEC_PER_HOUR, SEC_PER_DAY,
                              num2date, rrulewrapper, YearLocator,
                              MicrosecondLocator, warnings)

         是这里的warnings不能被引用，查阅相关文档后发现：

• matplotlib 3.2后的版本不在支持warnings
• Backtrader所支持的matplotlib版本为3.2.2
• 我安装的matplotlib是3.4.5
• 由此可以得出两种解决方案：

解决方案：

1、回退matplotlib版本为3.2.2

pip uninstall matplotlib
pip install matplotlib==3.2.2

2、将locator.py错误定位语句修改为：

from matplotlib.dates import (HOURS_PER_DAY, MIN_PER_HOUR, SEC_PER_MIN,
                              MONTHS_PER_YEAR, DAYS_PER_WEEK,
                              SEC_PER_HOUR, SEC_PER_DAY,
                              num2date, rrulewrapper, YearLocator,
                              MicrosecondLocator)
import warnings