Formatting the Output of Regular Expressions
Learn about the components of regular expressions and the art of desired outputs from regular expressions.
Components of a regular expression
Below are the basic components that make up a regular expression:
Characters : These appear in the string being matched. For example, the characters a and b appear in the string abc.
Metacharacters : These have a special meaning in a regular expression. For example, the metacharacter . (dot) matches any character.
Quantifiers : These specify how many of the previous characters, or groups of characters, must be present. For example, the quantifier * (asterisk) means “zero or more occurrences.”
Regular Expression Options : These change the way a regular expression is matched. For example, the i (ignore case) or RegexOptions.IgnoreCase option means that the case should be ignored when matching.
In the next section, we take a closer look at each of these components.
Characters
Characters are the most basic components of a regular expression. They match themselves in the string being matched.
For example, the character a matches the string a", aa, and aaa. However, it does not match b or cb.
Metacharacters
Metacharacters have a special meaning in a regular expression. They don’t match themselves. Instead, they match other characters or groups of characters.
For example, the ...