按年将 DataFrame 组织成列并按日月索引 - PYTHON - PANDAS

Question

I have a dataframe that I would like to plot by day and month, year on top of year. In order to do that I understand that I have to put the years into their own columns and index by day and month. I am not sure how to go at it.

Here is a sample data frame

    date    count
2012-11-12  219
2013-11-12  188
2014-11-12  215
2015-11-12  232
2012-11-13  210
2013-11-13  234
2014-11-13  220
2015-11-13  203
2012-11-14  224
2013-11-14  196
2014-11-14  213
2015-11-14  228

which should look something like this

day-month  2012 2013 2014 2015
11-12      219   188  215  232
11-13      210   234  220  203
11-14      224   196  213  228

Thanks

Answer 1

Use DataFrame.pivot_table

dates = pd.to_datetime(df['date'])
new_df = df.pivot_table(index=[dates.dt.month, dates.dt.day], 
                        columns=dates.dt.year, 
                        values='count')
new_df = (new_df.set_axis([f'{month}-{day}' for month, day in new_df.index])
                .rename_axis(index='month-day', columns=None)
              # .reset_index() # if you want column month-day 
         )
print(new_df)

Output

           2012  2013  2014  2015
month-day                        
11-12       219   188   215   232
11-13       210   234   220   203
11-14       224   196   213   228