时间戳

首页 > 解决方案 > 当输入无效时，如何停止 for 循环迭代？（不允许使用 while 循环）- Python

python - 当输入无效时，如何停止 for 循环迭代？（不允许使用 while 循环）- Python

问题描述

for i in range (0, 3): 
    
    print() # When iterates creates a space from last section
    
    raw_mark = int(input("What was student: " + str(student_id[i]) + "'s raw mark (0 - 100)?: "))
    
    days_late = int(input("How many days late was that student (0 - 5)?: "))
    
    penalty = (days_late * 5)
    
    final_mark = (raw_mark - penalty)

    # Selection for validation 
    
    if 0 <= raw_mark <= 100 and 0 <= days_late <= 5 and final_mark >= 40:
        
        print("Student ID:", str(student_id[i]))
        
        print() # Spacing for user readability
        
        print("Raw mark was:", str(raw_mark),"but due to the assignment being handed in",
              str(days_late),"days late, there is a penalty of:", str(penalty),"marks.")
        
        print()
        
        print("This means that the result is now:", final_mark,"(this was not a capped mark)")

         
        
    elif 0 <= raw_mark <= 100 and 0 <= days_late <= 5 and final_mark < 40: # Final mark was below 40 so mark must be capped
        
        print("Student ID:", str(student_id[i]))
        
        print()
        
        print("Raw mark was:", str(raw_mark),"but due to the assignment being handed in",
              str(days_late),"days late, there is a penalty of:", str(penalty),"marks.")
        
        print()
        
        print("Therefore, as your final mark has dipped below 40, we have capped your grade at 40 marks.")

        
    else:
        print("Error, please try again with applicable values")

在其他情况下，我希望循环循环返回，但没有将 i 迭代到下一个值，因此它可以是无限的，直到输入所有 3 个有效输入......不能使用 while 循环，我也不能放 if - elif- else 在循环之外。我也不能使用函数:(

标签： pythonfor-loopiteration

解决方案

尝试这样的事情。您可以跟踪有效输入的数量，并且只有在while达到目标数量后才停止循环（the ）。

valid_inputs = 0

while valid_inputs <= 3:
   ...

   if ...:
      ...
   elif ...:
      ...
   else:
      # Immediately reset to the top of the while loop
      # Does not increment valid_inputs
      continue

   valid_inputs += 1

推荐阅读