ประตูเฉลี่ยต่อทีมที่มีมากกว่า 56 ประตูและ 50 คะแนนพอดีคือเท่าไร?
What is the average goals against for teams with more than 56 goals for and exactly 50 points?
df = pd.DataFrame(columns=['goals_against', 'points_1', 'goals_for'])
df[(df['points_1'] == '50') & (df['goals_for'] > '56')]['goals_against'].mean()