Skip to main content

Quick Java : How to remove duplicate elements from an ArrayList or Vector

There are various algorithms to do so and if you want to implement any of those you are free to do so, but if you are using java this can be done in two lines!

As you know Sets don't allow duplicate elements, so why not use this property. Convert your ArrayList (or Vector or any other Collection for that matter) to Set and convert it back to your Collection.

In below code snippet, I have an ArrayList of integers named 'listOfNumbers'.


HashSet uniqueNumbers = new HashSet(listOfNumbers);  

Using HashSet will mess up the order of your elements, so if you are concerned about the order, use LinkedHashSet.

After conversion to set the duplicates are removed, convert it back to Collection object.

ArrayList listOfUniqueNumbers = new ArrayList(uniqueNumbers);

And you are done! How cool is that :)


Comments

Popular posts from this blog

Changing Eclipse Workspace Directory

Recently I moved my entire Eclipse installation directory but the workspace was still getting created in the older location only. And worst there was no option to select the Workspace directory in the Window->Options->Workspace menu. To change the workspace location in Eclipse do this. Goto ECLIPSE_HOME\configuration\.settings directory, edit the org.eclipse.ui.ide.prefs file and change the RECENT_WORKSPACES value to the desired location. If you want that Eclipse prompts you to select workspace when you start it, change the SHOW_WORKSPACE_SELECTION_DIALOG value to true. And you are done!

How to upload to Google Cloud Storage buckets using CURL

Signed URLs are pretty nifty feature given by Google Cloud Platform to let anyone access your cloud storage (bucket or any file in the bucket) without need to sign in. Official documentation gives step by step details as to how to read/write to the bucket using gsutil or through a program. This article will tell you how to upload a file to the bucket using curl so that any client which doesn't have cloud SDK installed can do this using a simple script. This command creates a signed PUT URL for your bucket. gsutil signurl -c 'text/plain' -m PUT serviceAccount.json gs://test_bucket_location Here is my URL: https://storage.googleapis.com/test_sl?GoogleAccessId=my-project-id@appspot.gserviceaccount.com&Expires=1490266627&Signature=UfKBNHWtjLKSBEcUQUKDeQtSQV6YCleE9hGG%2BCxVEjDOmkDxwkC%2BPtEg63pjDBHyKhVOnhspP1%2FAVSr%2B%2Fty8Ps7MSQ0lM2YHkbPeqjTiUcAfsbdcuXUMbe3p8FysRUFMe2dSikehBJWtbYtjb%2BNCw3L09c7fLFyAoJafIcnoIz7iJGP%2Br6gAUkSnZXgbVjr6wjN%2FIaudXIqA...

Hands on review: Yahoo! Mail app for Windows 8

Before you start mocking me for using Yahoo! Mail, let me explain that this is NOT my primary mail account and I use Gmail and Outlook.com for my daily use. Yes, this Yahoo! account was once my daily haunt but that was during college days and those days are long gone. I don't use Yahoo! Mail much but still there are some group subscriptions and I just log in once in a while to see what's happening in those forgotten groups. And due to this reason, I have always kept track of changes in Yahoo! Mail and the fact is that you can blame them for everything but not really lack of trying. Though most of those tries just ended up cluttering the UI and adding somewhat needless features. However, now we hear that new CEO Marissa Mayer is focusing once again on the mail and first major product to come out is Yahoo! Mail app for Windows 8. So how is it? The Login screen is pretty neat and purple background with an envelope watermark is very pleasing, very Yahoo!. However why ...