import pandas as pd
import numpy as np
import sys

print "\npandas version:",pd.__version__
define function to generate 3 level multi-index based dataframes
def gen_l3_mi(nchs,ndets,ntimes):
    "generate a 3-level multi-index dataframe"
    c = ['c'+str(i) for i in range(1,nchs+1)]
    det = ['d'+str(i) for i in range(1,ndets+1)]
    times = ['t'+str(i) for i in range(1,ntimes+1)]
    ind = []
    for ch in c:
        for d in det:
            for t in times:
                ind.append((ch,d,t))
    index = pd.MultiIndex.from_tuples(ind)
    return pd.DataFrame(np.random.randn(nchs*ndets*ntimes,3), 
                      columns=['A','B','C'],index=index)

df = gen_l3_mi(1,2,5)
df

df['D']=0.0

df.D.ix['c1','d1'].ix['t3':'t5'] = 1
df

grouped = df.groupby('D')

for i,j in grouped:
    print 'D:',i
    print 'Actual index[2]:',j.index[0][2]
    print 'First element of levels[2]:',j.index.levels[2][0]