How to drop double header resulting from pivot in Pandas?-CodePudding

Problem

I've done a pivot table in pandas, but I end up with a double header when I export to csv.

import pandas as pd

df = pd.DataFrame({'Year': [1, 2, 3, 4, 1, 2, 3, 4],
                   'Product': ['A', 'A', 'A', 'A', 'B', 'B', 'B', 'B'],
                   'net_sales': [55, 40, 84, 31, 56, 78, 34, 12]})
pvt_df = pd.pivot_table(df, values=['net_sales'], index=['Year'], columns=['Product'])
pvt_df.to_csv('sales.csv')

Which looks like below:

        net_sales   net_sales
Product A           B
Year        
1       55          56
2       40          78
3       84          34
4       31          12

Desired Result

What can I do to make the CSV export look like below?

Year    A           B
1       55          56
2       40          78
3       84          34
4       31          12

CodePudding user response：

You can try

pvt_df = pd.pivot_table(df, values='net_sales', index='Year', columns='Product').reset_index()
pvt_df.to_csv('sales.csv',index=False)

CodePudding user response：

Use pandas.DataFrame.droplevel with axis=1 to drop a level from the columns:

>>> pvt_df.droplevel(0, axis=1)
Product   A   B
Year           
1        55  56
2        40  78
3        84  34
4        31  12

>>> pvt_df.droplevel(0, axis=1).rename_axis(None, axis=1)
       A   B
Year        
1     55  56
2     40  78
3     84  34
4     31  12

>>> pvt_df.droplevel(0, axis=1).rename_axis(None, axis=1).reset_index()
   Year   A   B
0     1  55  56
1     2  40  78
2     3  84  34
3     4  31  12