Issue 1:
Code Sample, a copy-pastable example if possible

#Using pandas 0.19.2
import pandas as pd, pickle
arr= np.ones((5,5))
col= [ r'統合商C', r'統合商名', r'区分', r'H区分名' , r'H区' ]
df= pd.DataFrame(arr, columns=col)

with open( 'df_pandas_192.pkl', 'wb') as f:
pickle.dump(df, f, pickle.HIGHEST_PROTOCOL)

# Using pandas 0.20.1
import pickle
with open('df_pandas_192.pkl', 'rb') as f:
df= pickle.load(f)

Problem description

We have an issue due to module breaks

(probably dataframe class has been changed in 0.20.1)

/home/ubuntu/project27//aapackage/util_min.py in py_load_obj(folder, isabsolutpath, encoding1)
485 dir1= folder
486
--> 487 with open(dir1, 'rb') as f:
488 return pickle.load(f)
489
ModuleNotFoundError: No module named 'pandas.indexes'

Expected Output

Pickle serialized with this version pd.show_versions()

INSTALLED VERSIONS

commit: None

python: 2.7.12.final.0

python-bits: 64

OS: Windows

OS-release: 7

machine: AMD64

processor: Intel64 Family 6 Model 58 Stepping 9, GenuineIntel

byteorder: little

LC_ALL: None

LANG: en_US

LOCALE: None.None

pandas: 0.19.2

nose: 1.3.7

pip: 8.1.2

setuptools: 23.0.0

Cython: 0.24

numpy: 1.11.1

scipy: 0.18.0

statsmodels: 0.8.0

xarray: None

IPython: 4.2.0

sphinx: 1.4.1

patsy: 0.4.1

dateutil: 2.5.3

pytz: 2017.2

blosc: None

bottleneck: 1.1.0

tables: 3.4.2

numexpr: 2.6.0

matplotlib: 1.5.1

openpyxl: 2.3.2

xlrd: 1.0.0

xlwt: 1.1.2

xlsxwriter: 0.9.2

lxml: 3.6.0

bs4: 4.4.1

html5lib: None

httplib2: 0.10.3

apiclient: 1.6.2

sqlalchemy: 1.0.13

pymysql: 0.7.9.None

psycopg2: 2.6.2 (dt dec pq3 ext lo64)

jinja2: 2.8

boto: 2.40.0

pandas_datareader: None

Output of pd.show_versions()

INSTALLED VERSIONS
------------------
commit: None
python: 3.6.1.final.0
python-bits: 64
OS: Linux
OS-release: 4.4.0-1031-aws
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8

pandas: 0.20.1

pytest: 3.0.7

pip: 9.0.1

setuptools: 27.2.0

Cython: 0.25.2

numpy: 1.12.1

scipy: 0.19.0

xarray: None

IPython: 5.3.0

sphinx: 1.5.6

patsy: 0.4.1

dateutil: 2.6.0

pytz: 2017.2

blosc: None

bottleneck: 1.2.1

tables: 3.3.0

numexpr: 2.6.2

feather: None

matplotlib: 2.0.2

openpyxl: 2.4.7

xlrd: 1.0.0

xlwt: 1.2.0

xlsxwriter: 0.9.6

lxml: 3.7.3

bs4: 4.6.0

html5lib: 0.9999999

sqlalchemy: 1.1.9

pymysql: None

psycopg2: None

jinja2: 2.9.6

s3fs: None

pandas_gbq: None

pandas_datareader: None

Issue 2:
An example from

#20986 (comment)

from io import StringIO
from pandas import concat, DataFrame, read_table

buffer = StringIO("""\
study	SRP052491	SRP052491
run	SRR1762738	SRR1762739
gene_id
ENSG00000000003.14	16641	11561\
""")
expressions = read_table(buffer, header=[0, 1], index_col=[0])
third_index = DataFrame({'third_index': ['Disease X', 'Disease Y']}).T

concat([expressions, third_index], ignore_index=True)

Code Sample, a copy-pastable example if possible

# Your code here
a=raw_data.groupby(['Year','Month'])['Event_Count','Holiday_Count'].sum() -->shape=81,2
intermediate=raw_data[['Year','Month']].drop_duplicates() --> shape=81,2
raw_data=pd.concat([a,intermediate],ignore_index=True,axis=1)

Pandas version : '0.20.3'
python version : 3.6.3

Problem description

when i am truing to concat two dataframe with same dimension i am getting below error

Buffer dtype mismatch, expected 'Python object' but got 'long long'

[this should explain why the current behaviour is a problem and why the expected output is a better solution.]

Note: We receive a lot of issues on our GitHub tracker, so it is very possible that your issue has been posted before. Please check first before submitting so that we do not have to handle and close duplicates!

Note: Many problems can be resolved by simply upgrading pandas to the latest version. Before submitting, please check if that solution works for you. If possible, you may want to check if master addresses this issue, but that is not necessary.

For documentation-related issues, you can check the latest versions of the docs on master here:

https://pandas-docs.github.io/pandas-docs-travis/

If the issue has not been resolved there, go ahead and file it in the issue tracker.

Expected Output

Output of pd.show_versions()

[paste the output of pd.show_versions() here below this line]