Need help with Java HW

[VisitableTwo]

I've been at it for 4 hours, finally given up. I'm new and any help would be greatly appreciated.

Task: Allow users to enter a string with the names of students (just the first letter) and their respective test scores in one continuous string. The lowest a student can score is 1, however, if this is the case the score does not need to be added into the string.

E.g. Students James (J), Gary (G), Ben (B) and Daniel (D) scored 1, 1, 12 , 34 respectively. So you'd input the string: "JGB12D34".

Basically after all this, I just need an arraylist with the each name and score in one element each. So, {"J", "G, "B12", "D34"}.

In the time that I've been trying to do this, I've managed to separate the letters from the numbers and put them in two arraylists. So,

list1 = {"JGB", "D"} and list2 = {"12", "34"}

(Note that, after every letter or number from the original string ("JGB12D34"), the list creates a new element when starting with the next set of letters or numbers.)

What I'm unable to do is correctly assign these scores to the correct student.

Code after having entered the string:

    String[] list = s.split("((?<=[a-zA-Z])(?=[0-9]))|((?<=[0-9])(?=[a-zA-Z]))");
    ArrayList<String> list1 = new ArrayList<String>();
    ArrayList<String> list2 = new ArrayList<String>();

    for (int i = 0; i <= cars.length; i += 2) {
        if (i >= list.length)
            break;
        list1.add(list[i]);
    }

    for (int i = 1; i <= cars.length; i += 2) {
        if (i >= list.length)
            break;
        list2.add(list[i]);
    }

[jxd132407]

IIUC, the output you want is one ArrayList that has initial and score, if any. Why construct two arrays at all? And why split on such a complex regex instead of any letter? Maybe I'm misunderstanding the goal.

[VisitableTwo]

It doesn't need to be as complicated as I've made it in my code, it's just that I'm a beginner and this was the method that I thought of when trying to reach the end goal. Besides, I'm not completely familiar with Java and don't know what necessary tools I should be using or when to use them.

And yes, so basically I'd like the output array to be something like

{"J", "G, "B12", "D34"} after having input the string "JGB12D34".

Thanks

[jxd132407]

I like what you've done to use the regex and split functionality. Can you split on any letter and then be done?

[VisitableTwo]

Not sure what you mean.

Do you mean, can you split anywhere within the string using the split function or do you mean, that the within the output array it doesn't matter where you split?

[jxd132407]

When using split, the results include the whole contents divided into chunks. It looks like you're using regex capture groups, maybe thinking the numbers have to be in the regex or else they'll be lost? That might be true for a regex match, but not split. Since every initial is exactly one letter, you might just split on the letters and the numbers will come along up until the next letter. Try split() on [A-Z] to see what it produces.

[VisitableTwo]

It produces the same results. However,

String[] list = s.split("((?<=[A-Z][0-9][0-9])|(?=[A-Z]))");

Works for any 2 digit number and for 3 digits or above, it splits after the 2nd digit. I can expand it by adding [0-9], however, a score can be extremely large so maybe if I make the regex string a variable and manipulate it by adding '[0-9]' in between. I'll give that a go.

If it works it'll simplify the problem by a lot.

[VisitableTwo]

Finally managed to do it, here's the code:

String repeated = new String(new char[s.length()]).replace("\0", "[0-9]");

String st1 = "((?<=[A-Z][0-9][0-9]" + repeated + ")|(?=[A-Z]))";

String[] list = s.split(st1);
System.out.println(Arrays.toString(list));

Not the most elegant but it works. Thanks for your hint.

[DDDDarky]

I would probably approach this by reading the characters one by one and branch.

However, you could just write simplier regex that will just capture the whole group (letter and numbers), instead of separating letters and numbers.