Python 使用 do while 循环的出勤率计算器

Question

The aim is to create a percentage attendace calculator based on a given list of names. I was able to loop the input questions with the names in the list. However my issues lie with the following if condition which should output a 1 for each input question if the answer is y for each person in the list or a 0 if the answer n for any person in the list. The number outputs should then be added in order to obtain a precentage. Please help.

continueLooping=True

students=["Annie", "Brian", "Clare", "Danny", "Ellen"]

i=0

while i<len(students):
    askuser=input(f"Is {students[i]} present?[y/n]")
    i=i+1

    if askuser == "y":
        one = 1
        print("1")

    else:
        one = -1
        print("-1")

        while one<len(students):
            if askuser == "y":
               one = 1
                one=one+1
            else:
                one = -1
                one=one+1

percentage=(one)/len(students)
print(percentage)

Answer 1

Your second inner while loop will terminate only if the first answer is "y".

What you should be aiming to do is count the number of "y" answers you receive in the outer while loop. As such:

students=["Annie", "Brian", "Clare", "Danny", "Ellen"]

i=0
studentsPresentCount = 0

while i<len(students):
    askuser=input(f"Is {students[i]} present?[y/n]")
    i=i+1

    if askuser == "y":
        studentsPresentCount += 1




percentage = studentsPresentCount/len(students)
print(percentage)

Note you can use the syntactic sugar 'i += 1' instead of 'i = i + 1'.

Answer 2

In trying to stay as close to your code as possible, the code below works for what you describe.

There are three main corrections to the code:

1. You have an inner while loop that isn't necessary. On each pass of the outer while loop, you can ask about each student, output the desired attendance, and adjust the attendance score. There's no need for a second loop inside.

2. You keep changing the value of "one", rather than incrementing or decrementing. You can set one to 0 outside the loop (as you do with your counter i), and adjust it inside the loop.

3. You probably don't want non-attendance to be -1, but rather have it as zero. Imagine a scenario with 3 attendees and 2 non-attendees. Your scoring would end up with 1+1+1-1-1, for an attendance score of 1 - when in fact the attendance score is 3.

There's also no need for the "continueLooping" variable at the outset.

Last point, if you want percent, you can multiply the percentage value by 100 (as it is, it returns the decimal value).

The working code, with these corrections, is:

students=["Annie", "Brian", "Clare", "Danny", "Ellen"]

i=0
one = 0

while i<len(students):
    askuser=input(f"Is {students[i]} present?[y/n]")
    i=i+1

    if askuser == "y":
        one += 1
        print("1")

    else:
        print("0")



percentage=(one)/len(students)
print(percentage)