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up vote 2 down vote favorite

Ok im going to try and explain my problem here and what I need to do is convert a string array into an int array.

Here is part of what I have (well the initial set up)

   System.out.println("Please enter a 4 digit number to be converted to decimal ");
    basenumber = input.next();

    temp = basenumber.split("");
    for(int i = 0; i < temp.length; i++)
        System.out.println(temp[i]);

    //int[] numValue = new int[temp.length];
    ArrayList<Integer>numValue = new ArrayList<Integer>();

    for(int i = 0; i < temp.length; i++)
        if (temp[i].equals('0')) 
            numValue.add(0);
        else if (temp[i].equals('1')) 
            numValue.add(1);
                     ........
        else if (temp[i].equals('a') || temp[i].equals('A'))
            numValue.add(10);
                     .........
             for(int i = 0; i < numValue.size(); i++)
        System.out.print(numValue.get(i));

Basically what I am trying to do it set 0-9 as the actual numbers and then proceed to have a-z as 10-35 from the input string such as Z3A7 ideally would print as 35 3 10 7

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1  
What is the question? – Subhrajyoti Majumder Dec 5 '12 at 7:21
so what is the question? you want to optimize the code or you are getting some problems? – Bhavik Shah Dec 5 '12 at 7:25
The issue is that code I posted accepts the string and breaks it down into an array but that is all it does. It wont add values to a new array or change values. – mad hatter Dec 5 '12 at 8:05

3 Answers

up vote 2 down vote accepted

You can use this single line in the loop (assuming user doesn't enter empty string):

int x = Character.isDigit(temp[i].charAt(0)) ?
        Integer.parseInt(temp[i]) : ((int) temp[i].toLowerCase().charAt(0)-87) ;

numValue.add( x );

Explanation of the code above:

  • temp[i].toLowerCase() => z and Z will convert to the same value.
  • (int) temp[i].toLowerCase().charAt(0) => ASCII code of character.
  • -87 => Substracting 87 for your specification.
share|improve this answer
...that doesn't handle numbers, does it? – Jeff Dec 5 '12 at 7:29
That looks good, but I think you actually want 97 - "a" - not 87 - "W"... – Jeff Dec 5 '12 at 7:45
@Jeff Ascii for "Z" is 122 so we should subtract 87 to get 35, op specifies that. – Juvanis Dec 5 '12 at 7:47
Yeah, I just realised that and was changin my comment when you posted yours. My bad... – Jeff Dec 5 '12 at 7:48
I was trying this out me and a friend had discussed the ascii, but neither of us knew what to do about it. After I emplemented the code it threw an exception java.lang.StringIndexOutOfBoundersException: String index out of range: 0 @ java.lang.StringcharAt(Unknown Source) @ base.mainjava:38 and that is the first line of your code was there something I needed to import? – mad hatter Dec 5 '12 at 8:01
show 4 more comments
up vote 3 down vote

Try this in your loop:

Integer.parseInt(letter, 36);

This will interpret letter as a base36 number (0-9 + 26 letters).

Integer.parseInt("2", 36); // 2
Integer.parseInt("B", 36); // 11
Integer.parseInt("z", 36); // 35
share|improve this answer
Probably the easiest and most concise answer here. – Makoto Dec 5 '12 at 7:46
That's very cool, and I'm sure it should have been obvious to me... – Jeff Dec 5 '12 at 7:46
would this result in an Integer.parseInt(""); for every line that needed? If so that is fine I'm just curious and checking all the possible answers. – mad hatter Dec 5 '12 at 8:10
@madhatter, you would need to pass each letter through Integer.parseInt – RobEarl Dec 5 '12 at 9:38
up vote 0 down vote

Considering that you want to denote Z as 35, I have written the following function

UPDATE :

The ASCII value for Z is 90, so if you want to denote Z as 35 then you should subtract every character from 55 as (90-35=55):

public static int[] convertStringArraytoIntArray(String[] sarray) throws Exception {
    if (sarray != null) {
        int intarray[] = new int[sarray.length];
        for (int i = 0; i < sarray.length; i++) {
            if (sarray[i].matches("[a-zA-Z]")) {
                intarray[i] = (int) sarray[i].toUpperCase().charAt(0) - 55;
            } else {
                intarray[i] = Integer.parseInt(sarray[i]);
            }
        }
        return intarray;
    }
    return null;
}
share|improve this answer
That isn't going to work - you need to call toUpper() before subtracting I think – Jeff Dec 5 '12 at 7:36
1  
I know exactly where that magic number 55 comes from...but could you elaborate on it a bit? It's not immediately clear to others at first glance. – Makoto Dec 5 '12 at 7:37
@Makoto Thanks for suggestions.I have updated my answer accordingly. – Abhi_Mishra Dec 5 '12 at 7:40
Still needs to be toUppered. Otherwise "a" will result in 42 - which may be the answer to life, the universe and everything, but is probably not the desired answer... – Jeff Dec 5 '12 at 7:43
@Jeff Ofcourse it is desired answer..But now..:)..Thanks – Abhi_Mishra Dec 5 '12 at 7:47

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