Array processing in Java

Question

I have this String array in which is made up of string representing a student id, first name, last name, email,and grades. My question is: Is there away I can split each entry in this array and be able to calculate the average grade of student in this sample array entry. I would appreciate if anyone can offer some solution on how to achieve that in this array.

String[] students = {"1,John,Smith, John1010@fakemail.com ,20,88,79,59",
                     "2,Suzan,Erickson, Sue9999@fakemail.com ,19,91,72,85",
                     "3,Jack,Napoli, Jack789@fakemail.com,19,85,84,87",
                     "4,Erin,Black, Aaron888@fakemail.com,22,91,98,82"};

Please do some research and read the docs. You will easily be able to find out how you split a String. — SamTebbs33, Jun 28 '16 at 22:38
http://stackoverflow.com/questions/3481828/how-to-split-a-string-in-java This link should give you an idea on how to split up a string in Java. — Module, Jun 28 '16 at 22:41
google how to split strings in java and try your hands on. if you have difficulties then you come and paste your code with the problem you have. this is the only way we can help you. Nobody is going to write code for you here if you don't show us what you have tried so far. — Seek Addo, Jun 28 '16 at 22:41
`String[] rows = students.split(",");`Then `String[] columns = rows[0].split(",");` to get the first row (John Smith's) values for instance. — robotlos, Jun 28 '16 at 22:42
Do you need the average of each students or the total average? — Simon, Jun 28 '16 at 22:43

score 0 · Accepted Answer · answered Jun 29 '16 at 00:15

Here a piece of code that does what you want:

String[] students = ...
double[] averages = new double[students.length];

for (int i = 0; i < students.length; i++) {
    String[] student = students[i].split(",");
    int sum = 0;

    for (int j = 4; j < student.length; j++) {
        sum += Integer.parseInt(student[j]);
    }

    averages[i] = (double) sum / (student.length - 4);
}

The array averages will contain all the averages at the same position. Note that this code doesn't handle any wrong format and that it's assuming that all the remaining values are grades.

score -1 · Answer 2 · answered Jun 28 '16 at 22:51

I guess writing code for you will not be so appropriate... However, I can suggest what needs to be done: 1. Split each string by using String class split(regex). You can simply split the string with comma. (https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#split(java.lang.String)) 2. Just add the grade and divide by the size of students array.

I am sorry if you were expecting someone would provide the code...but learning by doing!!

what you are saying true and I already have a code for it – bencho Jun 28 '16 at 22:55 — bencho, Jun 28 '16 at 22:55

nunoymr · Answer 3 · 2016-06-28T22:59:03.293

public static void main(String[] args) {
    int grades = 0;
    String[] students = { "1,John,Smith,John1010@fakemail.com,20,88,79,59",
            "2,Suzan,Erickson,Sue9999@fakemail.com ,19,91,72,85", "3,Jack,Napoli,Jack789@fakemail.com,19,85,84,87",
            "4,Erin,Black,Aaron888@fakemail.com,22,91,98,82" };
    for (int i = 0; i < students.length; i++) {
        String[] student = students[i].split(",");
        for (int j = 4; j < student.length; j++) {
            grades += Integer.parseInt(student[j]);

        }
        grades=0;System.out.println(student[2] + ": " +(double) grades / (student.length - 4));
    }
}

@Nunomr, Thanks, I can see from your code exactly where i made the mistake in my initial code. — bencho, Jun 28 '16 at 22:57

Array processing in Java

3 Answers3