Let's step through the preceding code line by line to understand it.
In this line of code, we are assigning some text to a constant value:
let phrase: String = "The quick brown fox jumps over the lazy dog"
We define a new constant value by using the let keyword, and we give that constant a name, phrase. The colon : shows that we want to define what type of information we want to store in the constant, and that type is defined after the colon. In this case, we want to assign a string (String is how most programming languages refer to text). The = sign indicates that we are assigning a value to the constant we have defined, and "The quick brown fox jumps over the lazy dog" is a String literal, which means that it's an easy way to construct a string. Any text contained within "" marks is treated as a String literal by Swift.
We are assigning the String literal on the right-hand side of the = sign to the constant...
