JAVA : How can I reverse the string and parse it with '-' in Java-CodePudding

I have to reverse the given string and parse it with "-". for eg. INPUT: abcde OUTPUT : e-d-c-b-a Any simple solutions?

CodePudding user response：

Using StringBuilder#reverse we can try:

String input = "abcde";
StringBuilder sb = new StringBuilder(input);
String output = sb.reverse().toString().replaceAll("(?<=.)(?=.)", "-");
System.out.println(output);  // e-d-c-b-a

See this code run live at IdeOne.com.

For an explanation on the regex pattern used in String#replaceAll above, it aims to match every position in the string where there are letters on both side:

(?<=.)  assert that some character precedes
(?=.)   assert that some character follows

CodePudding user response：

Iterate the String in reverse. Join the output with -. Like,

String s = "abcde";
System.out.println(IntStream.range(0, s.length())
        .mapToObj(i -> String.valueOf(s.charAt(s.length() - i - 1)))
        .collect(Collectors.joining("-")));

CodePudding user response：

         String letters = "abcde";
          (int i = letters.length()-1; i >= 0; i--){
               char c = letters.charAt(i);
               System.out.print(c   "-");
           }