public class StringTest {
    public static void main(String[] args){
        String str1 = "ABCDEFG";
        String final1 = str1.substring(2,4);
        char final2 = str1.charAt(1);
        char final3 = str1.charAt(5);
        System.out.println(final1);
        System.out.println(final2);
        System.out.println(final3);

        String str = "A1B2C3D4E5F6G7H8";
        // original string numbers replaced without
        String final4 = str.replaceAll("\\d+","");
                 // original string of letters without replacing
        String final5 = str.replaceAll("\\D+","");
                 // The new pure string of letters
        String[] str2 = new String[final4.length()];
                 // The new pure numeric string
        int[] num = new int[final5.length()];
                 // string into the string array
        for(int i=0; i<final4.length(); i++){
              str2[i] = final4.charAt(i) + "";
        }
                 // Converts a string into integer array
        for(int i=0; i<final5.length(); i++){
            num[i] = Integer.parseInt(final5.substring(i,i+1));
        }
                 // traverse the new string array
        for(String str2s:str2){
            System.out.print(str2s);
        }
        System.out.println();
                 // iterate new array of integers
        for(int nums:num){
            System.out.print(nums);
        }
    }
}