Collections at a glance

So far, we’ve only needed variables to store a single value, but there are many conditions where a group of values will be required. Collection types in C# include arrays, lists, and dictionaries—each has its strengths and weaknesses, which we’ll discuss in the following sections.

Arrays

Arrays are the most basic collection that C# offers. Think of them as containers for a group of values, called elements in programming terminology, each of which can be accessed or modified individually:

• Arrays can store any type of value; all the elements need to be of the same type.
• The length, or the number of elements an array can have, is set when it’s created and can’t be modified afterward.
• If no initial values are assigned when it’s created, each element will be given a default value. Arrays storing number types default to zero, while any other type gets set to null or nothing.
• Arrays are the least flexible collection type in...