The Scala collections are a well-understood and frequently used programming abstraction that can be distinguished between mutable and immutable collections. Like a mutable variable, a mutable collection can be changed, updated, or extended when necessary. However, like an immutable variable, immutable collections cannot be changed. Most collection classes to utilize them are located in the packages scala.collection, scala.collection.immutable, and scala.collection.mutable, respectively.

This extremely powerful feature of Scala provides you with the following facility to use and manipulate your data:

• Easy to use: For example, it helps you eliminate the interference between iterators and collection updates. As a result, a small vocabulary consisting of 20-50 methods should be enough to solve most of your collection problem in your data analytics solution.
• Concise: You can use functional operations with a light-weight syntax and combine operations and, at the end, you will feel like that you're using custom algebra.
• Safe: Helps you deal with most errors while coding.
• Fast: most collection objects are carefully tuned and optimized; this enables you data computation in a faster way.
• Universal: Collections enable you to use and perform the same operations on any type, anywhere.

In the next section, we will explore the types and associated hierarchies of Scala collection APIs. We will see several examples of using most features in the collection APIs.