Choosing a collection

Here's the problem: after learning so many ways to make a collection of elements in Scala, it appears that we've got a big dilemma. We have quite a few options to choose from. Almost every collection has higher order functions to operate with. These are high-performing, type parameterized, and immutable collections. So how do we decide which collection to use? Now, we've the answer for that. And the answer is, it depends. Yes, it depends on multiple factors; for example, in which format would you like to have the data. Is it a simple sequence or in pair format? It's obvious that we've been talking about sequences, and maps up to now. In the majority of situations, we come up with Map, Set,List,ArrayBuffer, or a Vector. Let's talk about the factors that matter:

• If the requirement is to have a key-value lookup, we use Maps.
• We use HashMap when order is of no importance, and ListMap when we want to store the key-value pairs in a sequence. ListMap operations take linear time...