multiindex column in to_excel

[hayd]

link to #1651

Saving a multiindex column to_excel saves a sparse index.

Migrated from this StackOverflow question, with a smaller DataFrame.

In [1]: m = MultiIndex.from_tuples([(1,1),(1,2)], names=['a','b'])

In [2]: df = DataFrame([[1,2],[3,4]], columns=m)

In [3]: df
Out[3]: 
a  1   
b  1  2
0  1  2
1  3  4

In [4]: df.to_excel('test.xls')

Saves the xls:

    1.1 .2
0   1   2
1   3   4

This differs from how to_csv (which is not sparse):

,"(1L, 1L)","(1L, 2L)"
0,1,2
1,3,4

[joeb1415]

Both to_excel and to_csv should allow a multiindex on the columns to print on multiple rows

[jreback]

I guess then read_csv would have to take a list for the header argument to reconstruct the mi

#2478, this is already hiding in the codebase, just needs some TLC.

[jreback]

@hayd @jtratner IIRC this should still be open, right?

[jtratner]

yes, definitely.

[jmcnamara]

I think that has been fixed by #5423:

import pandas as pd

m = pd.MultiIndex.from_tuples([(1,1),(1,2)], names=['a','b'])
df = pd.DataFrame([[1,2],[3,4]], columns=m)

df.to_excel('test.xls')

Output:

Can we close this?

[mappingvermont]

Hi all,

I'm trying to write a multiindex dataframe to Excel using the example above, and not getting the same results.

Code:

import pandas as pd

m = pd.MultiIndex.from_tuples([(1,1),(1,2)], names=['a','b'])
df = pd.DataFrame([[1,2],[3,4]], columns=m)

df.to_excel('test.xls')

Output:

There's an extra line being added-- different than the output generated above.

I'm using pandas version 0.19.2 on Ubuntu 14.04 and have also experienced this on Windows 10. I've tried this using pandas version 0.15.0 and it works properly, replicating the output above:

Is this a bug? And if so, can we re-open this issue?

Thanks,

Charlie

[juandavid-bolanos]

@mappingvermont I'm getting the same result with a real example. I think it is a bug. Using latest version pandas 0.19.2

[ronanpaixao]

@jreback Can this be reopened? I also get this problem.

I've commented this on #6618, which seems related. From what I can see, the problem is that pandas is reserving the first column of the header rows to the MultiIndex, and creates a new line for the row index name even if it is unnamed:

>>> df = pd.DataFrame([[1,2,3],[4,5,6]], columns=pd.MultiIndex.from_tuples([('A'
,''),('B','C'),('B','D')]))
>>> df.to_excel("out.xlsx", index_label="Foo")

This bug was fixed some time ago for simple columns, but it was probably not a very good solution, since it is still buggy for MultiIndex columns:

>>> df = pd.DataFrame([[1,2,3],[4,5,6]], columns=['A','B','C'])
>>> df.to_excel("out.xlsx", index_label="Foo")

Version information:

>>> pd.show_versions()

INSTALLED VERSIONS
------------------
commit: None
python: 3.6.1.final.0
python-bits: 32
OS: Windows
OS-release: 7
machine: AMD64
processor: Intel64 Family 6 Model 42 Stepping 7, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

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: 3.2.2
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: 0.999
sqlalchemy: 1.1.9
pymysql: None
psycopg2: None
jinja2: 2.9.6
s3fs: None
pandas_gbq: None
pandas_datareader: None

[Tangjiahui26]

@jreback still got the same problem for the multi-index, wish this issue can be reopened.

[etiennecaldo]

Same here, I will open a new issue and try to find the problem

[Ronkiro]

@etiennecaldo Did you open the issue?
I'm having the same problem with the latest version of pandas.

[etiennecaldo]

@Ronkiro no I workarounded it on my side...!

[ferdiaoh]

This still appears to be an issue for multi-index columns (pandas 0.24.2) - is there any way this can be re-opened?

data = [[1, 2, 3, 4, 5, 6], [7, 8, 9, 10, 11, 12]]
multi_index = pd.MultiIndex.from_product([['a', 'b'], ['one', 'two', 'three']])
df = pd.DataFrame(data, columns=multi_index_one, index=[1, 2])

df.to_excel('test_files/test.xlsx')

pd.show_versions()
INSTALLED VERSIONS
commit: None
python: 3.6.6.final.0
python-bits: 64
OS: Darwin
OS-release: 18.6.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: None
LOCALE: en_IE.UTF-8
pandas: 0.24.2
pytest: 4.1.1
pip: 18.1
setuptools: 40.6.3
Cython: 0.28.2
numpy: 1.15.4
scipy: 1.1.0
pyarrow: 0.11.1
xarray: None
IPython: 7.2.0
sphinx: None
patsy: 0.5.1
dateutil: 2.7.5
pytz: 2018.7
blosc: None
bottleneck: None
tables: None
numexpr: None
feather: None
matplotlib: 3.0.2
openpyxl: None
xlrd: 1.2.0
xlwt: None
xlsxwriter: 1.1.8
lxml.etree: 4.3.0
bs4: 4.7.1
html5lib: None
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.10
s3fs: 0.2.0
fastparquet: None
pandas_gbq: None
pandas_datareader: None
gcsfs: None