What if instead of foo you wanted to find all words starting with the letter f, or all three letter words?Now you've gone beyond what literal strings can do (within reason)—it's time to learn some more about regular expressions.It is common when discussing regular expressions to analyze them based on text they would or would not match. The simplest regular expression is one you're already familiar with—the literal string.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.Jeffrey Friedl goes into more depth in his book, Mastering Regular Expressions (2 edition), which is strongly recommended for those wishing to learn more about the theory and history behind regular expressions.In the last five decades, regular expressions have slowly made their way from mathematic obscurity to a staple feature of many tools and software packages.
For example, x would match exactly five x characters (xxxxx).
Introduction Brief History of Regular Expressions Simple Expressions Quantifiers Metacharacters Character Classes Predefined Set Metacharacters Sample Expressions Validation in ASP.
NET Regular Expression API Free Tools Advanced Topics Conclusion Resources About the Author Support for regular expressions in the Microsoft®.
My goal is to validate the string "start0" with any second number I do the following: Please clarify your specific problem or add additional details to highlight exactly what you need.
As it's currently written, it’s hard to tell exactly what you're asking.