Convert binary List<String[]> to binary byte[] java with exact result

Question

I want to convert binary List to binary int[]. My code is as is below:

public class BinListToIntArr {
    public static void main(String[] args) {
        List<String[]> arrList = new ArrayList<>();

        //fill it
        arrList.add(new String[] {"0011","1100","1111","1111","0000"});
        arrList.add(new String[] {"0101","1111","1010","0000","0101"});
        arrList.add(new String[] {"1111","1010","0000","0101","1111"});
        arrList.add(new String[] {"1010","0000","1111","0101","1100"});
        arrList.add(new String[] {"0000","1110","1100","0001","0011"});

        //convert it
        ArrayList<Integer> ints = new ArrayList<>();
        for (String[] array : arrList) {
            for (String str : array) {
                ints.add(Integer.parseInt(str));
            }
        }

        Integer[] result = ints.toArray(new Integer[] {});

        for (int i : result){
            System.out.println(i);
        }
    }
}

The result supposed to be:

But I got this result:

In which part I made a mistake? Is there anybody can help? Because no matter I tried, 0 in String always disappear when I convert it into int. Is it possible to make 0 in String not disappear when we convert to int? If yes, how?

Hovercraft Full Of Eels · Accepted Answer · 2015-10-17 12:34:12Z

1

Don't confuse an int and a String representation of an int since an int is just a number and will never be able to understand or store something like leading 0's. If you want to display leading 0's then format your output. String.format(...) or System.out.printf(...) would work, for example:

  for (int i : result) {
     System.out.printf("%04d%n", i);
  }

Which outputs:

The "%04d" format specifier says print a String from an int that is four chars wide and that has leading 0's.

Edit: I forgot to add the %n within the format String since you wish to print a new line as well. This has now been added.

edited Oct 17, 2015 at 12:34

answered Oct 17, 2015 at 12:27

Hovercraft Full Of Eels

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3 Comments

user3698011 Over a year ago

It's working to print! So, the value itself doesn't change, right? I mean, the result both in List<String[]> is same with int[] result, am I correct?

Hovercraft Full Of Eels Over a year ago

@user3698011: the values are totally different. One hold Strings and one holds ints, two completely different types that hold different information.

user3698011 Over a year ago

Thank you for the explanation!

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