Remove duplicate elements in an ArrayList without using HashSet

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My Logic is messed up. I am just trying to work out a pay to remove duplicates in an arrayList without using a HashSet. public static void main(String[] args) { ArrayList<String> wordDulicate = new ArrayList<String>(); wordDulicate.add("Tom"); wordDulicate.add("Jones"); wordDulicate.add("Sam"); wordDulicate.add("Jamie"); wordDulicate.add("Robie"); wordDulicate.add("Helen"); wordDulicate.add("Tom"); wordDulicate.add("Troy"); wordDulicate.add("Mika"); wordDulicate.add("Tom"); for (String dupWord : wordDulicate) { if(wordDulicate.equals(dupWord)) System.out.println(wordDulicate.get(dupWord)); } } } java arraylist share|improve this question asked Oct 2 '12 at 19:46 AppSensei 73831336

Then you can create a new list and add items to it.. skipping duplicates.. –  Rohit Jain Oct 2 '12 at 19:48 2   Just out of curiosity or is use of HashSet prohibited by the teacher? :) –  halex Oct 2 '12 at 19:48 how is for (int dupWord : wordDulicate) { compiling? –  gtgaxiola Oct 2 '12 at 19:48 Does this even compile? –  Tudor Oct 2 '12 at 19:49 dupWord should be a String not an int –  doublesharp Oct 2 '12 at 19:49  show 2 more comments

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This methodology requires having another list: ArrayList<String> wordDulicate = new ArrayList<String>(); wordDulicate.add("Tom"); wordDulicate.add("Jones"); wordDulicate.add("Sam"); wordDulicate.add("Jamie"); wordDulicate.add("Robie"); wordDulicate.add("Helen"); wordDulicate.add("Tom"); wordDulicate.add("Troy"); wordDulicate.add("Mika"); wordDulicate.add("Tom"); ArrayList<String> nonDupList = new ArrayList<String>(); Iterator<String> dupIter = wordDulicate.iterator(); while(dupIter.hasNext()) { String dupWord = dupIter.next(); if(nonDupList.contains(dupWord)) { dupIter.remove(); }else { nonDupList.add(dupWord); } } System.out.println(nonDupList); Output: [Tom, Jones, Sam, Jamie, Robie, Helen, Troy, Mika] share|improve this answer answered Oct 2 '12 at 19:50 Nambari 38.5k43363

3   Why are you removing from original list? –  maba Oct 2 '12 at 19:55 I thought that was requirement, if NOT, we can do just ! (NOT) check. –  Nambari Oct 2 '12 at 19:56  I'm new to Iterator. Can I ask why you used to Iterator? –  AppSensei Oct 2 '12 at 20:01 Iterator allows you to loop through the collection. docs.oracle.com/javase/1.5.0/docs/api/java/util/Iterator.html–  Nambari Oct 2 '12 at 20:03 So, is that the best way to loop through a collection? –  AppSensei Oct 2 '12 at 20:05 show 3 more comments