How to group by one column and count frequency from other column for each item in the previous column in python? I am trying to group my data by the 'ID' column. Then I want to count the frequency of 'sequence' for each 'ID'. Here is a sample of the data frame:

ID     Sequence
101    1-2
101    3-1
101    1-2
102    4-6
102    7-8
102    4-6
102    4-6
103    1118-69
104    1-2
104    1-2


I am looking for a count same as:

ID   Sequence   Count
101    1-2        2   
       3-1        1
102    4-6        3
       7-8        1
103    1118-69    1
104    1-2        2


I tried this code in python which doesn't give me what I want


  df.groupby('ID') 
  Blockquote


df.groupby('Sequence').count()
This simple Code worked:

Count_sequence = df.groupby(['ID','Sequence']).count()


For obtaining the output in an excel sheet:

Count_sequence.to_excel('sequence_count.xlsx)