String index out of range when writing in specific line in a Textfile

Question

Why does it keeps giving me this error? I have this in my first method but it doesn't give me an error, but when I use the code in the 2nd method it continue giving me this error

This is my first method, it works well,

    def btn_English(self):
    answerKey = open("answerkeyEnglish", 'r')
    studentExam = open("studentExam", 'r')
    index = 0
    numCorrect = 0

    for answerLine, studentLine in zip(answerKey, studentExam):
        answer = answerLine.split()
        studentAnswer = studentLine.split()
        if studentAnswer != answer:
            print("You got question number", index + 1, "wrong\nThe correct answer was", answer, "but you answered",
                  studentAnswer)
            index += 1
        else:
            numCorrect += 1
            index += 1
    gradeAverage = int((numCorrect / 2) * 100)
    grade = numCorrect
    english = open('examResult','w')
    english.write(str(grade))

and this the second method, where it gives the error. in english.write(str(grade)[2]).

    def btn_Math(self):
    answerKey = open("answerkeyEnglish", 'r')
    studentExam = open("studentExam", 'r')
    index = 0
    numCorrect = 0

    for answerLine, studentLine in zip(answerKey, studentExam):
        answer = answerLine.split()
        studentAnswer = studentLine.split()
        if studentAnswer != answer:
            print("You got question number", index + 1, "wrong\nThe correct answer was", answer, "but you answered",
                  studentAnswer)
            index += 1
        else:
            numCorrect += 1
            index += 1
    gradeAverage = int((numCorrect / 2) * 100)
    grade = numCorrect
    english = open('examResult','r')
    english.write(str(grade)[2])

Can someone tell me why I'm getting this error because in the first method it works well, but in the 2nd method it gives error?

What are you trying to accomplish with `english.write(str(grade)[2])`? What does the `[2]` represent to you? Also you open the file in read mode with `english = open('examResult','r')` but then try to write to it, that's going to fail. — Alex Hall, Feb 25 '19 at 20:36
what should I do? if I remove the string it gives this error ? write() argument must be str, not int. — Jefer P. Bulan, Feb 25 '19 at 20:40
I want to write in the 3 line of the textfile @AlexHall. Is my code there gonna work ? — Jefer P. Bulan, Feb 25 '19 at 20:42
I want to write in the specific line in the text file. And that is the 2nd problem whether I will use 'a' or 'w'? — Jefer P. Bulan, Feb 25 '19 at 20:44
@JeferP.Bulan See this for writing in the specific line: https://stackoverflow.com/a/45187717/10625520 — Heyran.rs, Feb 25 '19 at 20:50
Obtain all the grades without writing anything to a file, then afterwards open the file once and write each grade, all in one go. — Alex Hall, Feb 25 '19 at 20:53
@AlexHall what approach or how can I do write each grade all in one go? sorry I'm new in programming. — Jefer P. Bulan, Feb 25 '19 at 20:57
Thanks sir its much clearer now. @AlexHall what is the 'grades' variable in the code that you are given? and where should I put it? sorry I'm just little confused now. — Jefer P. Bulan, Feb 25 '19 at 21:20

score 0 · Answer 1 · answered Feb 25 '19 at 20:34

0

str(grade)[2] gives the third character of str(grade), which only exists if grade is a number with 3 or more digits.

answered Feb 25 '19 at 20:34

Alex Hall

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grade is only single digit, what should I do to make my code work ? – Jefer P. Bulan Feb 25 '19 at 20:41
How can I write in specific line in a textfile? is .write(str(grade)[2]) gonna work or I nee to change something because the character that will be inputted is single digit? – Jefer P. Bulan Feb 25 '19 at 20:50

String index out of range when writing in specific line in a Textfile

1 Answers1