Why my PanelND factory throwing a KeyError?

Question

I\'m using Pandas version 0.12.0 on Ubuntu 13.04. I\'m trying to create a 5D panel object to contain some EEG data split by condition.

Ho

Answer 1

Working example. You needed to specify the mapping of your axes to the internal axes names via the slices. This fiddles with the internal structure, but the fixed names of pandas still exist (and are somewhat hardcoded via Panel/Panel4D), so you need to provide the mapping.

I would create a Panel4D first, then your Subject as I did below.

Pls post on github / here if you find more bugs. This is not a heavily used feature.

Output

<class 'pandas.core.panelnd.Subject'>
Dimensions: 3 (setsize) x 1 (location) x 1 (vfield) x 10 (channels) x 2 (samples)
Setsize axis: level0_0 to level0_2
Location axis: level1_0 to level1_0
Vfield axis: level2_0 to level2_0
Channels axis: level3_0 to level3_9
Samples axis: level4_1 to level4_2

Code

import pandas as pd
import numpy as np
from pandas.core import panelnd

Subject = panelnd.create_nd_panel_factory(
    klass_name='Subject',
    axis_orders=['setsize', 'location', 'vfield', 'channels', 'samples'],
    axis_slices={'location' : 'labels',
                 'vfield' : 'items',
                 'channels' : 'major_axis',
                 'samples': 'minor_axis'},
    slicer=pd.Panel4D,
    axis_aliases={'ss': 'setsize',
                  'loc': 'labels',
                  'vf': 'items',
                  'major': 'major_axis',
                  'minor': 'minor_axis'})


subjects = dict()
for i in range(3):
    eeg = pd.DataFrame(np.random.randn(10,2),columns=['level4_1','level4_2'],index=[ "level3_%s" % x for x in range(10)])

    loc, vf = ('level1_0','level2_0')
    subjects["level0_%s" % i] = pd.Panel4D({ loc : { vf : eeg }})

print Subject(subjects)