Selecting, Filtering & Sorting

df['Calories'] — one column, as a Series. df[['Duration', 'Calories']] — several columns, as a DataFrame (note the double brackets: a list inside the brackets).

Drop columns you don't need: df.drop(columns=['Maxpulse']). Rename them: df.rename(columns={'Calories': 'kcal'}).

Selecting only the columns you need keeps output readable and memory low.