请尝试以下代码

print ("""Enter the names of all the pupils in your class.
Type 'Stop' to indicate that all the names have been entered.""")

count_names = 0 # Initialize count_names to 0

while True:
    pupil_names = input("Enter a name: ")
    
    if pupil_names == "Stop":
            print(f"There are {count_names} students")
            break

    count_names += 1 # Add 1 each time we count a pupil

通过将count_names设置为{}，您将其设置为 * dictionary *，这不符合您的目的。您可以将所有名称保存到 * list *（[]）中，或者只将名称的数量保存为数字（以0开始）。

names_list = [] # version 1
names_count = 0 # version 2

while True:
    new_name = input("Enter a name: ")

    if new_name == "Stop":        
        break

    names_list.append(new_name) # version 1
    names_count += 1            # version 2

print(f"There are {len(names_list)} students") # version 1
print(f"There are {names_count} students")     # version 2

此外，我将print语句放在while-block之外，因为您的任务需要它。它将运行完全相同。

将count_names更改为：

count_names = 0

并添加以下一行：

while True:
  pupil_names = input("Enter a name: ")
  count_names += 1

这个应该能用

我希望这对你有帮助，因为这是我对这个问题的看法：

print('''Enter the names of all the pupils in 
the class. Enter "Stop" once all the names have 
been entered.
''')

pupil_count = 0

while pupil_count >= 0:
   pupil_names = input("Enter a name: ")

   pupil_count += 1

   if pupil_names == "Stop":

       print(f"\nThe total number of pupils in the class is: {pupil_count - 1}")

       break