Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time


Regextra is a small library built to address problems that are handily solved by regular expressions.

Currently, the library includes the following features:

  • Passphrase Regex Builder
  • Named Template Formatting
  • Useful regex/string methods

How do I get started?

  • Check out the wiki
  • Visit the project's demo site for a chance to try out some client-side validation (using the patterns produced by the PassphraseRegex builder)
  • The extensive test suite is worth a glance

Regextra is available via NuGet:

PM> Install-Package Regextra 

Passphrase Regex Builder

A common question I've seen on StackOverflow is how to write code that enforces strong passphrase or password rules. Popular responses tend to tackle the problem by using a regex with look-aheads. I've seen this so much that I decided to have fun writing a solution that allowed people to produce regex patterns that would enforce such rules.

Example usage

The following code generates a pattern to enforce a password of 8-25 characters that requires at least two lowercase letters in the range of a-z and numbers excluding those in the range of 0-4 (i.e., numbers in the 5-9 range are acceptable).

var builder = PassphraseRegex.With.MinLength(8)
                                  .IncludesRange('a', 'z')
                                  .ExcludesRange(0, 4);

PassphraseRegexResult result = builder.ToRegex();

if (result.IsValid)
    if (result.Regex.IsMatch(input))
        // passphrase meets requirements
        // passphrase is no good
    // check the regex parse exception message for the generated pattern

Refer to the PassphraseRegex wiki for further details and examples.

Template Formatting

Template formatting allows you to perform named formatting on a string template using an object's matching properties. It's available via the static Template.Format method and the string extension method, FormatTemplate. The formatter features:

  • Nested properties formatting
  • Dictionary formatting
  • Standard/Custom string formatting
  • Escaping of properties
  • Detailed exception messages to pinpoint missing properties
  • Great performance (in part thanks to FastMember)

Example usage

var order = new
    Description = "Widget",
    OrderDate = DateTime.Now,
    Details = new
        UnitPrice = 1500

string template = "We just shipped your order of '{Description}', placed on {OrderDate:d}. Your {{credit}} card will be billed {Details.UnitPrice:C}.";

string result = Template.Format(template, order);
// or use the extension: template.FormatTemplate(order);

The result of the code is:

We just shipped your order of 'Widget', placed on 2/28/2014. Your {credit} card will be billed $1,500.00.

Refer to the Template wiki for further details and examples.

RegexUtility Class

This static class features a couple of helpful methods, such as:

  • Split Methods

    • Split
    • SplitRemoveEmptyEntries
    • SplitIncludeDelimiters
    • SplitMatchWholeWords
    • SplitTrimWhitespace
  • Formatting Methods

    • TrimWhitespace
    • FormatCamelCase
  • Named Groups Conversion Methods

    • MatchesToNamedGroupsDictionaries
    • MatchesToNamedGroupsLookup

Refer to the RegexUtility wiki for further details and examples.

OSS Libraries Used

Regextra makes use of the following OSS libraries:

Core Contributor

Regextra is Copyright © 2013-2014 Ahmad Mageed under the MIT license.


Regextra simplifies some tasks typically solved via regex so that you no longer have (problems){2}







No packages published