Export to excel for multiindex columns

Hi All,

I’m just using 0.17 for testing exporting multiindex column dataframe. When i’m pivot table dataframe with X column as index (and without “columns” argument), which will not create multiindex column,

pivot table code (without columns argument):

df.pivot_table(index=["X"], columns=[], aggfunc={"Y": len,"Z":np.sum}, fill_value=0)
df.to_excel(FILE_NAME)

the output using to_excel() follow new format:

But, the question arise when i’m trying to pivot table X column as index (and with “columns” argument), which will create multiindex columns. Then, i’m trying to export it using to_excel() and still follow old format.

pivot table code (with columns argument):

df.pivot_table(index=["X"], columns=["A"], aggfunc={"Y": len,"Z":np.sum}, fill_value=0)
df.to_excel(FILE_NAME)

I don’t know if this newest excel export format only applied to single column index, not multicolumn index. Was this case expected or there is something wrong?

Thanks

[sakinaljana]

@chris-b1 : Correct, the concern is more to the feature consistency. I assume if new format will be applied to both single column and multi index column. Thanks for clarifying this!!

@jreback : Yeah, it’s perfectly works for doing both write and read from excel. But, it seems more elegant if the index column going up one level, see the following example:

But then, i found new error (i don’t know if this already fixed or not). When i’m trying to write excel with not including index (index = False), it throw exception.

NotImplementedError: Writing to Excel with MultiIndex columns and no index ('index'=False) is not yet implemented.

The code is like this

df = pd.DataFrame(data={"X":["test1","test2","test3","test4","test5","test5", "test2", "test3"],"Y":[0,1,2,2,1,2,10,3], "Z": [1000,300,400,500,2350,100,100,1000], "A":["category1","category2","category2","category3","category4","category4","category5","category1"]})

# pivot df with column argument
df_with_col_arg = df.pivot_table(index=["X"], columns=["A"], aggfunc={"Y":np.sum,"Z":np.sum}, fill_value=0)

# resetting index
df_with_col_arg.reset_index(inplace=True)

# write to excel with no index
df_with_col_arg.to_excel("excel-with-no-index.xlsx", index=False)

Any idea?

[hsheikha1429]

Had the same error issue and writing here as a reference to tell what fix it in my case:

Having the index=True fixed my case, the export from df to excel showed the multi Indexing in perfect understood position. filename = os.path.join(outputDir, "named_df.xls") # .xls or .xlsx doesn't matter df.to_excel(filename, ### index=True)