BUG: Index name lost when using .loc with list of indices

[jason-curtis]

When using DataFrame.loc with a list of indices, the index name is missing from the resultant DataFrame unless the list of indices includes all of the indices in the original DataFrame.

Example:

import pandas as pd
d=pd.DataFrame(
    [
        [1,2,3],
        [4,5,6],
        [7,8,9]
    ], 
    columns=['i','j','k']
).set_index('i')

When I use .loc and ask for all of the rows, I get (as desired) the correct, named index out the other end:

d.loc[[1,4,7]]
#    j  k
# i      
#1  2  3
#4  5  6
#7  8  9

d.loc[[1,4,7]].index.name
# 'i'

When I ask for a list of indices that is not all of them, I also expect to get a named index out the other end. However, the index values are preserved but the index name is lost:

d.loc[[1,4]]
#    j  k
#1  2  3
#4  5  6

d.loc[[1,4]].index.name
# None

Suggesting that this is a bug because the index naming should be the same no matter whether I .loc for for all of the rows or just some of them.

[jason-curtis]

pd.show_versions() output:

INSTALLED VERSIONS
------------------
commit: None
python: 2.7.6.final.0
python-bits: 64
OS: Linux
OS-release: 3.13.0-24-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.14.0
nose: 1.3.3
Cython: 0.19.1
numpy: 1.8.1
scipy: 0.13.3
statsmodels: 0.5.0
IPython: 2.1.0
sphinx: 1.2.2
patsy: 0.2.1
scikits.timeseries: None
dateutil: 2.2
pytz: 2014.4
bottleneck: None
tables: 3.1.2dev
numexpr: 2.4.1.dev
matplotlib: 1.3.1
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: None
html5lib: 0.999
bq: None
apiclient: None
rpy2: None
sqlalchemy: None
pymysql: None
psycopg2: 2.4.5 (dt dec mx pq3 ext)

[jreback]

this works in master/0.15 (IIRC fixed for 0.14.1 as well), but don't remember off-hand

try out the rc1

http://pandas.pydata.org/

[jason-curtis]

Never mind then. Thanks!

[immerrr]

This is a duplicate of #6552, should be fixed in 0.15.