Ruby Array Filter Duplicates

Learn how to manually remove duplicates from an array in ruby without using the uniq method.

Ruby array filter duplicates.

Ruby program that finds duplicates in an array def find duplicates elements encountered examine all elements in the array. Build a method that returns all of the duplicates from an array in ruby. Even numbers 1 2 3 4 5 6 each do n if n even. Array 1 2 1 3 5 4 5 5 1 2 1 3 5 4 5 5 dup array select element array count element 1 1 1 5 5 5 dup uniq 1 5 share.

For example you can find all the even numbers in a list. If the array is empty the first form returns nil and the second form returns an empty array. P often when writing ruby programs either in rails or say as part of a script its useful to be able to select or filter nbsp data in ruby itself. Some of those methods are set and filter.

In this guide we ll add a method to the array class that returns all duplicates. In order to find the duplicated elements i use this approach with ruby 1 9 3. Ruby has a helpful method for removing duplicates from an array the uniq method. Each do e if the element is in the hash it is a duplicate.

Share a link to this answer. The elements are chosen by using random and unique indices into the array in order to ensure that an element doesn t repeat itself unless the array already contained duplicate elements. The uniq method returns a new array with all duplicate values removed. Show activity on this post.

For better understanding lets discuss each method individually. This answer is not useful. E else record that the element was encountered. You could iterate through the array and filter out the duplicates but ruby s uniq method makes that a lot easier.

While we would usually do this in the database say via activerecord a database isn t always available. You can use the select method in ruby to filter an array of objects. Let s learn how to use select. Without select that looks like this.

However there are times when you simply want to know which elements in an array are duplicates. N end end even numbers that s quite a bit of code for something so simple. Elements bird dog bird cat find duplicates elements output dupe exists for. Removing duplicates to remove duplicates in an array we have many logical methods but advanced javascript has provided some methods so that the task of removing duplicates has become very simple.