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Need to reverse a string in Java

Hi Folks,

I need an easy way to reverse a string in java, but not character by character, but separated by a fullstop.

For example .. I need

127.0.0.2
to be reversed to
2.0.0.127

Another example

192.168.0.1
to be reversed to
1.0.168.192

Any help would be much appreciated.

Cheers.
0
JigsawTech
Asked:
JigsawTech
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1 Solution
 
sciuriwareCommented:
Easiest:  split into numbers,
reverse the numbers,
rebuild the string.

;JOOP!
0
 
sciuriwareCommented:
String original = "127.0.0.2";

String[] k = original.split("\\.");

String new = k[3] + '.' + k[2] + '.' + k[1] + '.' + k[0];

;JOOP!
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grahamcorpCommented:
I would imagine you could break this into smaller substrings based on the '.'?
So for example,
Sorry if the syntax etc isn't right, but hopefully you get the idea?
May not be most efficient solution.

String ip = '192.168.0.1';
 
String [] tempIP = ip.split('.');
 
public static string reverseJoin( String[] ip, String delimiter)
{
   ip = reverseArray(ip);
 
   StringBuffer buffer = new StringBuffer();
   Iterator iter = ip.iterator();
 
   while(iter.hasNext())
   {
      buffer.append(iter.next());
      if( iter.hasNext() )
      {
          buffer.append(delimiter)
      }
   }
   return buffer.toString();
}
 
private static reverseArray(String [] arrayToReverse)
{
   String [] tempArray;
 
   for( int i = 0; i < tempIP.length; i++ )
   {
      tempArray[i] = tempIP[tempIP.length-i];
   }
   
   return tempArray;
}

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grahamcorpCommented:
I wasn't sure if the ip thing was just an example, i.e. is the string also going to be in the format <num>.<num>.<num>.<num>?
If it is then sciuriware is a better solution than mine as mine will be overkill.
0
 
darkappleCommented:
Ok here is a function i've created to reverse string as per your requirement.
	private String strRev(String str){
		
		String rev = "";
 
		String[] k = str.split("\\.");
		
 
		for(int i=k.length; i!=0; i--){
			
			rev = rev.concat(k[i-1]);
			rev = ((i-1)>0?rev.concat("."):rev.concat(""));
		}
 
		return rev;
	}

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0
 
JigsawTechAuthor Commented:
Thanks alot, works great.
0
 
JigsawTechAuthor Commented:
hi folks,

Appreciate the speedy responses .. didn't even think about using split..  doh.

Thanks again.
0
 
sciuriwareCommented:
Have a good time with avaJ.

!POOJ;
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