Regular expressions

Matching in a query string parameter

I feel documentation on any regex is important and they are super hard to read / understand.

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/// <summary>
/// $                                        -> String interpolation
/// @"                                       -> Starts a verbatim string literal.
/// (                                        -> Logical grouping of part of an expression.
/// (\&|\?)                                  -> Start with `&` or `?`
/// ?                                        -> Result of `(\&|\?)` must be 0 or 1
/// \b                                       -> Matches a word boundary
/// {SomeAttribute.Hoe}=1                    -> String interpolation, if `SomeAttribute.Hoe` was `42` then this would add `42=1`
/// \b                                       -> Matches a word boundary
/// </summary>
private readonly string MyQueryStringParamRegex = $@"((\&|\?)?)\b{SomeAttribute.Hoe}=1\b";

You could then use this in code as

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if (new Regex(MyQueryStringParamRegex).IsMatch(query))
{
     // do something based on the match
}

Matching email address

Sweet example from computerhope.com to match an Email address.

Email Matching Example

References