這是《Python forEverybody》練習(xí) 9.2 中的一個問題我的問題是，為什么當(dāng) for 循環(huán)嵌套在 for 循環(huán)中時，天數(shù)計數(shù)會發(fā)生變化？這是我的代碼，它提供了正確的答案：{'Sat': 1, 'Fri': 20, 'Thu': 6}file_name = input("Enter a file name: ")file_handle = open(file_name)day_count_list = []day_count_dict = dict()for line in file_handle:    line = line.strip()    if line.startswith("From "):        line = line.split()        day_counts = line[2]        day_count_list.append(day_counts)        for day in day_count_list:    day_count_dict[day] = day_count_dict.get(day, 0) + 1print(day_count_dict)然而，當(dāng)for循環(huán)嵌套時，答案就變成了：{'Sat': 27, 'Fri': 330, 'Thu': 21}for line in file_handle:    line = line.strip()    if line.startswith("From "):        line = line.split()        day_counts = line[2]        day_count_list.append(day_counts)        for day in day_count_list:            day_count_dict[day] = day_count_dict.get(day, 0) + 1