ABSTRACT
Most programming languages supply their users with a menu of built-in collection types, each offering a specific balance of useful features and efficient data processing, that together cover a range of scenarios. One way of comparing different types of collections is to examine the way in which they store and provide access to data. Like variables in some languages, collections may be constructed such that they contain only certain categories of objects. Sets are collections of unique elements, and are valued for their ability to enforce the restriction that, no matter the type of objects stored, no two objects are identical. In the absence of any outstanding factors, statements in code are generally executed from top to bottom, in the order that they appear in a script. In this imperative model of programming, control flow statements are those syntactical structures that alter the continuous stream of execution, diverting the shell to some distant codeblock.
