Group by 和 value_counts - 将结果作为列返回

Question

I have a DF of the following:

    value     name     
      A      Steven     
      A      Steven    
      A      Ron    
      B      Joe     
      B      Steven     
      B      Ana       

I want to perform a value_counts() operation on the name column so the output will be a DF where the columns are the counters of the values :

     value  Steven Ron  Joe Ana   
      A       2     1    0   0
      B       1     0    1   1            
      

Tried a group by+value_counts and than transposing the results but didn't reached the output.

Answer 1

It is crosstab

pd.crosstab(df.value, df.name).reset_index().rename_axis(None,1)

Out[62]:
  value  Ana  Joe  Ron  Steven
0     A    0    0    1       2
1     B    1    1    0       1

Answer 2

You can do this with groupby and value_counts like this:

df.groupby('value')['name'].value_counts().unstack(fill_value=0).reset_index()

Output:

name value  Ana  Joe  Ron  Steven
0        A    0    0    1       2
1        B    1    1    0       1