set_index breaks depending on column name or number

[PhE]

I get a very strange behaviour with pandas current dev version (tagged as '0.9.0rc2') :
Calling set_index() on a DataFrame breaks depending on the columns name I use !!!

This code fails :

df3 = DataFrame({
    '0001-INTERNAL_PRODUCT_CODE': {('A', 'A0006000', 'nuit'): 'A0006000'},
    '0004-PACKAGING_LANGUAGE_CODE': {('A', 'A0006000', 'nuit'): nan},
    '1050-LOCALISED_DESCRIPTION': {('A', 'A0006000', 'nuit'): nan},
    '0024-PRODUCT_BAR_CODED': {('A', 'A0006000', 'nuit'): nan},
    'Source system': {('A', 'A0006000', 'nuit'): 'A'}, 
    '0027-LOCAL_COMMERCIAL_AUTHORIZATION': {('A', 'A0006000', 'nuit'): nan},
})
df3.set_index(['0001-INTERNAL_PRODUCT_CODE', '1050-LOCALISED_DESCRIPTION']) # fails !

But If I change the indexed column names to 'a' and 'x', It works :

df3 = DataFrame({
    'a': {('A', 'A0006000', 'nuit'): 'A0006000'},
    '0004-PACKAGING_LANGUAGE_CODE': {('A', 'A0006000', 'nuit'): nan},
    'x': {('A', 'A0006000', 'nuit'): nan},
    '0024-PRODUCT_BAR_CODED': {('A', 'A0006000', 'nuit'): nan},
    'Source system': {('A', 'A0006000', 'nuit'): 'A'}, 
    '0027-LOCAL_COMMERCIAL_AUTHORIZATION': {('A', 'A0006000', 'nuit'): nan},
})
df3.set_index(['a', 'x']) # works !

At first I thought It was related to column name .... but If I keep my exotic column name and remove one column (one not used by set_index), it works !! :

df3 = DataFrame({
    '0001-INTERNAL_PRODUCT_CODE': {('A', 'A0006000', 'nuit'): 'A0006000'},
    '1050-LOCALISED_DESCRIPTION': {('A', 'A0006000', 'nuit'): nan},
    '0024-PRODUCT_BAR_CODED': {('A', 'A0006000', 'nuit'): nan},
    'Source system': {('A', 'A0006000', 'nuit'): 'A'}, 
    '0027-LOCAL_COMMERCIAL_AUTHORIZATION': {('A', 'A0006000', 'nuit'): nan},
})
df3.set_index(['0001-INTERNAL_PRODUCT_CODE', '1050-LOCALISED_DESCRIPTION']) # works !

[lodagro]

on master:

In [9]: df3.set_index(['0001-INTERNAL_PRODUCT_CODE', '1050-LOCALISED_DESCRIPTION'])
Out[9]: 
                                                       0004-PACKAGING_LANGUAGE_CODE  0024-PRODUCT_BAR_CODED  0027-LOCAL_COMMERCIAL_AUTHORIZATION Source system
0001-INTERNAL_PRODUCT_CODE 1050-LOCALISED_DESCRIPTION                                                                                                         
A0006000                   nan                                                  NaN                     NaN                                  NaN             A

However, this way you are using NaN in the index, which is a no-no, see also #1971.

[wesm]

Can this be closed?

[changhiskhan]

Don't think so. Looks like this is broken on master now. Another instance of na support issues with MultiIndex.
It's not dependent on the column name. It's the call to Index.summary that craps out and the format in the difference use cases differ.

[wesm]

I'll have a look. After food, though