DSES DataFrame Operations Quiz

Which function sorts a DataFrame df by the column 'Salary' in ascending order?

• df.sort_values('Salary')

• df.sort('Salary')

• df.order_by('Salary')

• df.arrange('Salary')

What does df.dropna(subset=['Age']) do?

• Drops rows where 'Age' is missing

• Drops all columns with missing values

• Fills missing 'Age' values with zero

• Drops the 'Age' column

How do you select rows where 'Department' is 'HR'?

• df[df['Department'] == 'HR']

• df.query('Department = HR')

• df.filter('HR')

• df.select('Department == HR')

What is the output of df.groupby('City')['Population'].sum()?

• Total population per city

• Average population per city

• Number of cities

• Sorted population values

How do you add a column 'Tax' as 15% of 'Income'?

• df['Tax'] = df['Income'] * 0.15

• df.insert('Tax', df['Income'] * 0.15)

• df.assign(Tax = df.Income * 0.15)

• df.new_column('Tax', df['Income'] * 0.15)

What does df.describe() return?

• Summary statistics for numeric columns

• Column names

• Missing value counts

• First 5 rows

How do you rename the column 'OldName' to 'NewName'?

• df.rename(columns={'OldName': 'NewName'})

• df.columns.replace('OldName', 'NewName')

• df['NewName'] = df['OldName']

• df.set_column_name('OldName', 'NewName')

What does df['Age'].mean() compute?

• Average age

• Median age

• Mode age

• Minimum age

How do you drop the column 'Temp' from df?

• df.drop(columns=['Temp'])

• df.remove('Temp')

• df.delete('Temp')

• df.drop_column('Temp')

What does df.duplicated().sum() return?

• Number of duplicate rows

• Sum of all values

• Count of unique rows

• Index of duplicates