reindex a pandas.panel with a MultiIndex

Question

I was trying to reindex a Panel with a MultiIndex. The ultimate goal is to be able to do slicing like this:

wp.loc[(1,slice(None)),:,:] #Access the panel fixing the first index of the multiIndex

But whenever I try to reindex, like in this example I got this strange behaviour.

wp = pd.Panel(pd.randn(4, 5, 4), items=['Item_1_1', 'Item_1_2','Item_2_1','Item_2_2'],major_axis=['a','b','c','d','e'],minor_axis=['A', 'B', 'C', 'D'])
a=[tuple([int(i) for i in item.split('_')[1:]]) for item in wp.items]
swp=wp.reindex(items=x)

But when I try to access an item of the panel I got;

In [101]: swp[1,1]
Out[101]: 
    A   B   C   D
a NaN NaN NaN NaN
b NaN NaN NaN NaN
c NaN NaN NaN NaN
d NaN NaN NaN NaN
e NaN NaN NaN NaN

What am I doing wrong?

Answer 1

您的新索引是一个元组列表，因此现在每个项目的索引都为（1,1），（1,2）等。为了访问该项目，我假设您尝试使用swp[1,1]进行访问必须简单地索引swp[(1,1)] （即panel[item_name] ）。