Character classes are a way of combining characters with common traits into a single classification, such as characters that represent numbers, letters, vowels, or hexadecimal characters. Once we get into the details, we will see how useful character classes are. So, in this section, we're going to take a look at introducing the basics of character classes. We'll expound on that by introducing character class ranges, character class negations, and then we will write a full regular expression to handle matching dates.
So, our first introduction to character classes begins with vowels. Vowels are the letters A, E, I, O, U. Almost every word has a vowel in it. Let's see if we can write a character class that matches a vowel:
So, here we have word "dog" and, to begin a character class, we use square braces. Inside the square braces we have...
