Tip 16: Keep Unique Values with Set

Set

Set is a fairly simple collection that can do only one thing, but it does it very well. Set is like a specialized array that can contain only one instance of each unique item. You’ll often want to collect values from a large array of objects, but you only need to know the unique values. There are other use cases as well, but collecting a list of distinct information from a group of objects is very, very common.

Example

In that spirit, return once again to our set of filters that you’re building. To even know what a user can filter on, you need to gather all the possible values. Recall the array of dogs that you worked with earlier.