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Java RegEX To Split and Reverse String

Anonymous User361028-Sep-2013
I have a Java String "test/this/string" that I want to reverse to "string/this/test" using a regular expression or the most efficient Java algorithm. The way I know is to use the split method, loop over the array and rebuild the string manually. The number of "/" can vary and doesn't occur a fixed number of times. Any ideas?
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Updated on 28-Sep-2013
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Anonymous User

Anonymous User

28-Sep-2013

Hey Tanuja!

Here's my take:

String input = "test/this/string"; 
List<String> list = Arrays.asList(input.split("(?=/)|(?<=/)")); 
Collections.reverse(list); 
StringBuilder sb = new StringBuilder(); 
for (String s: list) 
   sb.append(s); 
System.out.println(sb.toString());

(?<=/) is a zero-length matching regex that matches if the previous character is a /.

(?=/) is a zero-length matching regex that matches if the next character is a /.

So (?=/)|(?<=/) matches right before and after each /, thus the split splits the string

into"test", "/", "this", "/", "string".

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