รายชื่อผู้เล่นที่ไม่มีโค้ช
List the names of players that do not have coaches.
df_player = pd.DataFrame(columns=['Player_name', 'Player_ID']); df_player_coach = pd.DataFrame(columns=['Player_name', 'Player_ID'])
df_player[~df_player['Player_ID'].isin(df_player_coach['Player_ID'])]['Player_name']