Regular expression for validating time in
Below are some sample patterns and inputs they would match. (period or dot) metacharacter is one of the simplest and most used. This can be useful for specifying that certain patterns can contain any combination of characters, but must fall within certain length ranges by using quantifiers.
The constructs within regular expressions that have special meaning are referred to as metacharacters. Also, we have seen that expressions will match any instance of the pattern they describe within a larger string, but what if you only want to match the pattern exactly?
A particular string can be described, literally, by itself, and thus a regular expression pattern like foo would match the input string foo exactly once.
In this case, it would also match the input: The food was quite tasty, which might be not be desired if only a precise match is sought.
This article covers the basics and recommends where to go to learn more. I hope it will also make a handy reference/refresher for developers who have used regular expressions before, in conjunction with my regular expression cheat sheet. NET Regular Expression API Summary: Regular expressions are an extremely useful tool for working with text.Introduction Brief History of Regular Expressions Simple Expressions Quantifiers Metacharacters Character Classes Predefined Set Metacharacters Sample Expressions Validation in ASP.Quantifiers always refer to the pattern immediately preceding (to the left of) the quantifier, which is normally a single character unless parentheses are used to create a pattern group.Below are some sample patterns and inputs they would match.