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C# Static RegexUse a static Regex. Understand the benefits of static Regex instances.
Static Regex. A static Regex helps performance. It can be used throughout methods in the C# program. This reduces allocations and can simplify programs.
Single-instance Regex. A static Regex is essentially a single-instance regular expression. Static regular expressions have clear performance advantages.
Regex
To start, we demonstrate the use of a static Regex. You can use a static variable initializer at the class level to instantiate the regular expression with the new operator.
Then You can access the Regex by its identifier and call methods such as Match, Matches and IsMatch on it.
Regex.Matches
Next This program finds the first word starting with a capital R in the input string.
Tip The biggest benefit of static Regex instances is that they will not likely be created more than once.
Info Your regular expression can be shared between many different methods on the type. This will improve performance.
C# program that uses static Regex instance
using System; using System.Text.RegularExpressions; class Program { static Regex _rWord = new Regex(@"R\w*"); static void Main() { // Use the input string. // ... Then try to match the first word starting with capital R. string value = "This is a simple /string/ for Regex."; Match match = _rWord.Match(value); Console.WriteLine(match.Value); } }
Regex
Performance. Static regular expressions show a performance advantage. Static fields do not have an instance expression, so resolving the location of their memory storage is slightly faster.
Performance, continued. Regular expressions are not an ideal solution for performance. They can be sped up with considerations of their allocation patterns, as with the static modifier.
Static
A summary. We implemented a static regular expression. This can improve performance by enhancing the access patterns to the regular expression and restricting heap allocations.
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