I need to replace non-digit characters from an array of String and return a String with digits separated by coma, actually, I made it but don't like it.

The first thing I made, was added values from the String array to the String.

Then I replaced non-digit characters from a String.

After that, I added digit values to an int array and sorted it.

Then I added all this stuff to an array of strings and separated values with commas, after that I returned it.

I would be glad for advice, thanks for attention.

import java.util.Arrays;

class Test {

    private static String sortedStringOfNumber(String[] string) {

        StringBuilder temp = new StringBuilder();

        for (String s: string) {
            temp.append(s);
        }

        String numberOnly = temp.toString().replaceAll("[^0-9]", "");

        int[] numbers = new int[numberOnly.length()];
        for (int i = 0; i < numberOnly.length(); i  ) {
            numbers[i] = numberOnly.charAt(i) - '0';
        }

        Arrays.sort(numbers);

        String[] result = new String[numbers.length];

        for (int i = 0; i < numbers.length; i  ) {

            result[i] = String.valueOf(numbers[i]);
        }

        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < result.length; i  ) {
            sb.append(result[i].toString());
            if (i != result.length - 1)
                sb.append(", ");
        }
        return sb.toString();
    }

    public static void main(String[] args) {
        String[] arrayStringData = new String[] { "1", "ab3c", "level", null, "java2s.com", "asdf 456", "Br0C0de" };

        //Should be "0, 0, 1, 2, 3, 4, 5, 6"
        System.out.println("Sorted string of numbers ->\t"   sortedStringOfNumber(arrayStringData));
    }
}

CodePudding user response：

Your solution would run in O(n*log n) mainly due to Arrays.sort.

Use a simple counting sort. This would give you a runtime of O(n).

Look at the string and ignore all other non-digits.