for循环内的Python While循环在值无效时继续重复

Question

这是我的代码：

for i in range(1, 5):
    try:
        grade = int(input("Please enter {}'s grade for practical assessment {}: ".format(name, i)))
        while (grade < 0 and grade > 40):
            print("That is not a valid grade.")
            continue
    except ValueError:
        print("That is not a valid value.")
        continue

我的问题是，如果输入错误的输入，如何检查成绩是否在范围内，并使循环重复。 当我尝试运行该程序并输入一个超出范围的输入时，它将转到下一个评估编号，而不是再次尝试直到正确为止。

Answer 1

您可以使用类似以下内容的代码，该代码使用while True循环以及try statement and except clause来确定用户是否输入了有效成绩：

names = ["Adam", "Bob", "Chloe"] # Example list of names

for name in names:
  for i in range(1, 5):
    while True:
      try:
        grade = int(input("Please enter {}'s grade for practical assessment {}: ".format(name, i)))
        if not (0 <= grade <= 40):
          raise ValueError()
      except ValueError:
        print("Error: Please enter a grade between 0 and 40")
      else:
        break

用法示例：

Please enter Adam's grade for practical assessment 1:  a
Error: Please enter a grade between 0 and 40
Please enter Adam's grade for practical assessment 1:  -1
Error: Please enter a grade between 0 and 40
Please enter Adam's grade for practical assessment 1:  10
Please enter Adam's grade for practical assessment 2:  4
Please enter Adam's grade for practical assessment 3:
...

在这里尝试！