为什么pandas datareader返回数据框而不是面板，我尝试了我知道的所有方法
companies = ["MSFT", "GOOG", "AAPL", "Y", "AMZN"]
mask = web.DataReader(name = companies, data_source = "yahoo", start = "2010-01-01", end = "2016-12-31")
mask
我希望使用面板说明而不是数据框 像这样
<class 'pandas.core.panel.Panel'>
Dimensions: 5 (items) x 1688 (major_axis) x 5 (minor_axis)
Items axis: Open to Volume
Major_axis axis: 2010-01-04 00:00:00 to 2016-09-16 00:00:00
Minor_axis axis: AAPL to YHOO