Python While循环位于for循环中，该循环在值无效时不断重复

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

我的问题是如何检查分数是否在范围内，如果输入了错误的输入，如何使循环重复。当我试图运行程序并输入一个超过范围的输入时，它会转到下一个评估数字，而不是再次尝试，直到它是真的。

Answer 1

您可以使用类似这样的方法，使用while True循环以及try语句和except子句来确定用户是否输入了有效的分数：

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:
...

在这里试试！