How to convert a string of numbers into integers?

Question

I want to convert a string of 5 numbers separated by commas into integers and store them into an array.

// person class
public class Person {
    private String Name;
    private char sex;
    private String score;
    private int[] grades = new int[5];
    private String newName;
    public Person()   // CONSTRUCTOR
    {

    }

    public void fixName()
    {
        String lower = Name.toLowerCase();
        int a = Name.indexOf(" ",0);
        String first = lower.substring(0, a);
        String last = lower.substring(a+1);
        char f = first.charAt(0);
        char l = last.charAt(0);
        f = Character.toUpperCase(f);
        l = Character.toUpperCase(l);
        String newname = "" + l + last.substring(1) + " " + f + first.substring(1);
    } 
    public void fixScore()
    {
        int b = score.indexOf(",", 0);
        int i = Integer.parseInt(b);
        String[] b = score.split(",", 5);

        System.out.print(b);
    }
}

Answer 1

1. Mark your question as "Homework"
2. Split your string using comma as a delimiter.
3. Extract each int from the string using ParseInt
4. Add these ints to your array.

Answer 2

Assuming you have:

String data = "1, 23, 456, 789";

...then use String#split to get individual strings for each number, create an int[] array of the same length as the resulting array, loop through the resulting array using String#trim to trim each entry and Integer#parseInt to parse them. It will end up looking something like this (untested):

String[] parts;
int results[];
int index;

parts = data.split(",");
results = new int[parts.length];
for (index = 0; index < parts.length; ++index) {
    results[index] = Integer.parseInt(parts[index].trim());
}

Naturally there are some things not handled in the above, like for instance what to do if you have two commas in a row and parts[index].trim() is therefore blank.

Answer 3

stating the obvious:

String input = "1,2, 4,  10    ,20";

String[] parts = input.split(",");
int[] numbers = new int[parts.length];

for(int i = 0; i < parts.length; i++)
    numbers[i] = Integer.parseInt(parts[i].trim());

return numbers;

Answer 4

It's really easy to do in Java... First you need to define some interfaces:

public interface ArrayConverter<I,O> {
    O chop (I input);
}

public interface ArrayTransmogrifier<I,O> {
    O convert (I input);
}

Then you need some concrete implementations:

public class CommaStringToArrayConverter implements ArrayConverter<String,String[]> {

    public String[] chop(String input) {
       return input.split(",");
    }
}

public class StringToIntTransmogrifier implements ArrayTransmogrifier<String[], int[]>{

    public int[] convert(String[] input) {
        int[] ret = new int[input.length];

        for (int i = 0; i < input.length; i++) {
            ret[i] = Integer.parseInt(input[i]);
        }

        return ret;
    }

}

Now, you need some factories to create them. I'd recommend using a IOC container, but that is probably over your head at this point, so we will do a simple abstract factory:

public class ArrayConverterFactory {
    public ArrayConverter GetConverter(String type) {

        if (type.equals("CommmaStringToArrayConverter"))
            return new CommaStringToArrayConverter();

        return null;
    }
}


public class ArrayTransmogrifierFactory {
   public ArrayTransmogrifier GetTransmogrifier(String type) {

        if (type.equals("StringArrayToIntArray"))
            return new StringToIntTransmogrifier();

        return null;
    }
}

And with all that done, it is very simple to do the conversion:

public static void main(String[] args) {

   String inputString = "5,4,3,2,1";

   ArrayConverterFactory factory1 = new ArrayConverterFactory();
   ArrayConverter converter = factory1.GetConverter("CommmaStringToArrayConverter");

   String[] splitString = (String[])converter.chop(inputString);

   ArrayTransmogrifierFactory factory2 = new ArrayTransmogrifierFactory();
   ArrayTransmogrifier transmogrifier = factory2.GetTransmogrifier("StringArrayToIntArray");

   int[] results = (int[])transmogrifier.convert(splitString);

}