CODEWITHSUNDEEP
javamethods
cooljcat
cooljcat

Reputation: 31

How do I make a method that inserts dashes into a string in a looping pattern?

For context, the method needs to insert dashes into a string in a 1, 2, 4, 1, 2, 4... pattern. For example, a string that holds "Overflow" would be output as "O-ve-rflo-w". Would I use nested for loops in this situation?

Upvotes: 1

Views: 293

Answers (4)

flauschpantoffel
flauschpantoffel

Reputation: 1

Method:

private static String addDashes(String string, int... pattern) {
    String output = "";
    int index = 0;

    while (true)
        for (int p : pattern) {
            if (index + p >= string.length())
                return output += string.substring(index);
            output += string.substring(index, index += p) + "-";
        }
}

Call Method:

System.out.println(addDashes("Overflow", 1,2,4));

Output:

O-ve-rflo-w

Upvotes: 0

sorifiend
sorifiend

Reputation: 6307

The other answer using a pattern is a great solution, however, you could also use a recursive method. This may not be a compact solution, but the logic is easy to follow:

//Process the string in chunks of 7 characters
public static String addFormatting(String input){
    String formatted = "";
    
    //Add first character
    if(input.length() >= 1) formatted = input.substring(0, 1);
    
    //Add dash and the next 2 characters, else the remainder of the string
    if(input.length() >= 3) formatted += "-" + input.substring(1,3);
    else if (input.length() > 1) formatted += "-" + input.substring(1);
    
    //Add dash and the next 4 characters, else the remainder of the string
    if(input.length() >= 7) formatted += "-" + input.substring(3,7);
    else if (input.length() > 3) formatted += "-" + input.substring(3);
    
    //Add dash and recursivly format the next chunk
    if(input.length() > 7){
        formatted += "-";
        return formatted + addFormatting(input.substring(7));
    }
    //else return the complete formatted once it has been fully processed
    else return formatted;
}

To call the method simply use addFormatting("OverflowisagreatQnAsite!"); the printed output would O-ve-rflo-w-is-agre-a-tQ-nAsi-t-e!

Upvotes: 2

Most Noble Rabbit
Most Noble Rabbit

Reputation: 2776

You can do the following:

private static String applyPattern(List<Integer> pattern, String str) {
    int currentPatternIndex = 0;
    int iterationsTillNextDash = pattern.get(currentPatternIndex);
    StringBuilder stringBuilder = new StringBuilder();
    
    for (char aChar : str.toCharArray()) {
        if (iterationsTillNextDash == 0) {
            stringBuilder.append('-');
            iterationsTillNextDash = pattern.get(++currentPatternIndex % pattern.size());
        }

        iterationsTillNextDash--;
        stringBuilder.append(aChar);
    }
    return stringBuilder.toString();
}

Usage:

String strWithDashes = applyPattern(Arrays.asList(1, 2, 4), "Overflow");
System.out.println(strWithDashes);

Output:

O-ve-rflo-w

Upvotes: 2

NeonFire
NeonFire

Reputation: 186

Here is a simple hard-coded example for your situation. Perhaps you can figure out a way to use modulus % in your code for words longer than "overflow".

class Main {
  public static String addDashes(String s)
  {
    String s_with_dashes = "";
    for(int i = 0; i < s.length(); i++)
    {
      if(i == 1 || i == 3 || i == 7)
      {
        s_with_dashes += '-';
      } 
      s_with_dashes += s.charAt(i);   
    }
    return s_with_dashes;
  }
  public static void main(String[] args)
  {
    String s = "Overflow";
    String s_with_dashes = addDashes(s);
    System.out.println(s_with_dashes);
  }
}

Upvotes: 0

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