Pandas transposition inside dataframe

问题

I have this datasate now:

animal   age             count
dogs     1               49
         2              134
         3              147
         4              154
cats     1              189
         2              254
         3              259
         4              261

I would like to convert age column to 4 age columns for each age:

animal   age1 age2 age3 age4 
dogs      49   134  147  154  
cats     ....................   

I have tried df.T and df.transpose() but both of them return my original column.

回答1:

You could use pd.pivot:

In [25]: result = df.pivot(index='animal', columns='age', values='count')

In [26]: result
Out[26]: 
age       1    2    3    4
animal                    
cats    189  254  259  261
dogs     49  134  147  154

In [27]: result.columns = ['age{:d}'.format(col) for col in result.columns]

In [28]: result
Out[28]: 
        age1  age2  age3  age4
animal                        
cats     189   254   259   261
dogs      49   134   147   154

来源：https://stackoverflow.com/questions/24116600/pandas-transposition-inside-dataframe