Set and Sorted Set

Set

A Redis set data type is similar to a set data structure that you may have used in programming languages such as Java. The two most important characteristics of a set in Redis are:

• They contain unique strings only. In other words, duplicate elements are not allowed.

• There are no ordering guarantees. When we retrieve items from a set, they may not be in the same order as when we added them to the set.

Just like the string data type, a set in Redis seems simple, but it includes a rich set of features. Let’s explore a few of them in the following sections.

The SAdd method

To do anything useful with a set, we first need to add items to it. We can do that with the SAdd method. In the example below, we add three fruits (apple, orange, and banana) to a set called fruits: