python groupby count()

The groupby() function in Python is used to group the data based on a specific column. The count() function is used to count the number of occurrences of each group.

Here is an example of how to use groupby() and count() functions in Python:

import pandas as pd

# create a sample dataframe
df = pd.DataFrame({'Name': ['John', 'Mary', 'John', 'Peter', 'Mary'], 
                   'Age': [25, 35, 30, 45, 40], 
                   'City': ['New York', 'Los Angeles', 'Chicago', 'Houston', 'Miami']})

# group by the 'Name' column and count the number of occurrences
count_df = df.groupby(['Name']).count()

print(count_df)

Output:

       Age  City
Name           
John     2     2
Mary     2     2
Peter    1     1

In the above example, we have grouped the data by the 'Name' column and counted the number of occurrences of each name. The resulting dataframe shows the count for each name.