Why is my replacement only producing the last value in a list that I have passed through a function?

I have a list (letter_grades) that has four "X" in it (each corresponding to a student grade). I need to use a function to calculate letter grades from a previously existing list (student_grades = [98, 87, 67, 89]). Finally, I want to take that information and replace the "X" values in letter_grades with the values I got using student_grades.

So, if I calculated that the first student scored 98, the function told me that was an A, I want to replace the X with the A (in the correct order). In theory I’d end up with letter_grades = A, B, D, B.

I feel like I am really close (but maybe not). Here is what I have so far. My issue is that it is only changing the values to the last item in the list. I assume it’s because of how print works, but I am having trouble figuring out how else to solve this.

student_grades = [98, 87, 67, 89]
letter_grades = ['X','X','X','X']

def Gradecalc(list):
    if score >= 90:
        letter = 'A'
    else:   
        if score >= 80:
            letter = 'B'
        else:  
            if score >= 70:
                letter = 'C'
            else:    
                if score >= 60:
                    letter = 'D'
                else:
                    letter = 'F'
    return letter

for value in range(len(letter_grades)):
        letter_grades[value]=letter_grades[value].replace("X", Gradecalc(student_grades))
    
print(letter_grades)

The output just gives me [‘B’, ‘B’, ‘B’, ‘B’] – which is the last anticipated value of letter_grades.

Am I close? How do I get it to print the correct values?

>Solution :

Actually, your code snippet produces errors.
As mentioned in the comment, score used but not defined.

Here’s how your code can be changed:

student_grades = [98, 87, 67, 89]
letter_grades = ['X','X','X','X']

def Gradecalc(score):
    if score >= 90:
        letter = 'A'
    elif score >= 80:
        letter = 'B'
    elif score >= 70:
        letter = 'C'
    elif score >= 60:
        letter = 'D'
    else:
        letter = 'F'
    return letter

for value in range(len(letter_grades)):
    letter_grades[value] = letter_grades[value].replace("X", Gradecalc(student_grades[value]))
    
print(letter_grades)

Output:

['A', 'B', 'D', 'B']

I changed the argument of Gradecalc to score.

Then changed the calling of Gradecalc(student_grades) to Gradecalc(student_grades[value]) (only one grade, not all of them at one time).

Also, nested if..else can be rewritten as if..elif..else, makes code more readable.