


Why is `\d` Less Efficient Than `[0-9]` for Digit Matching in C# Regex?
Jan 31, 2025 pm 06:26 PM
The reason for is lower than d
[0-9]
is unexpectedly lower than the d
and [0-9]
character set. This discovery triggered two problems: [0123456789]
higher efficiency than setting ? [0-9]
[0123456789]
People may think that the scope is more efficient, because it covers a specific and narrow character range, and the collection clearly lists all ten numbers. However, the test results show that the performance differences between the two methods are the least.
The efficiency of
is lower than?
d
Test found that the efficiency of is significantly lower than [0-9]
. This is particularly puzzling, because is usually considered as abbreviation of
d
[0-9]
matching unicode numbers, d
matching ASCII numbers [0-9]
with only ASCII numbers (0-9), d
match [0-9]
all unicode numbers . This includes characters from other languages ??and characters, such as Persian numerals (?????????) and Dava Garri numerals (??????????). To prove this, the following code generates a string containing all Unicode numbers:
[0-9]
The generated string shows d
various characters identified as numbers, including characters from Arabic, Thai, Khamno, and other characters.
Performance impact
var sb = new StringBuilder(); for (UInt16 i = 0; i < 0x10FFFF; i++) { if (char.IsDigit((char)i)) { sb.Append((char)i); } } string unicodeDigits = sb.ToString();
Check the wide range of character range (unicode numbers and ASCII numbers) explaining the performance differences between d
and
will produce better performance than .
The above is the detailed content of Why is `\d` Less Efficient Than `[0-9]` for Digit Matching in C# Regex?. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

Yes, function overloading is a polymorphic form in C, specifically compile-time polymorphism. 1. Function overload allows multiple functions with the same name but different parameter lists. 2. The compiler decides which function to call at compile time based on the provided parameters. 3. Unlike runtime polymorphism, function overloading has no extra overhead at runtime, and is simple to implement but less flexible.

C has two main polymorphic types: compile-time polymorphism and run-time polymorphism. 1. Compilation-time polymorphism is implemented through function overloading and templates, providing high efficiency but may lead to code bloating. 2. Runtime polymorphism is implemented through virtual functions and inheritance, providing flexibility but performance overhead.

Yes, polymorphisms in C are very useful. 1) It provides flexibility to allow easy addition of new types; 2) promotes code reuse and reduces duplication; 3) simplifies maintenance, making the code easier to expand and adapt to changes. Despite performance and memory management challenges, its advantages are particularly significant in complex systems.

C destructorscanleadtoseveralcommonerrors.Toavoidthem:1)Preventdoubledeletionbysettingpointerstonullptrorusingsmartpointers.2)Handleexceptionsindestructorsbycatchingandloggingthem.3)Usevirtualdestructorsinbaseclassesforproperpolymorphicdestruction.4

People who study Python transfer to C The most direct confusion is: Why can't you write like Python? Because C, although the syntax is more complex, provides underlying control capabilities and performance advantages. 1. In terms of syntax structure, C uses curly braces {} instead of indentation to organize code blocks, and variable types must be explicitly declared; 2. In terms of type system and memory management, C does not have an automatic garbage collection mechanism, and needs to manually manage memory and pay attention to releasing resources. RAII technology can assist resource management; 3. In functions and class definitions, C needs to explicitly access modifiers, constructors and destructors, and supports advanced functions such as operator overloading; 4. In terms of standard libraries, STL provides powerful containers and algorithms, but needs to adapt to generic programming ideas; 5

Polymorphisms in C are divided into runtime polymorphisms and compile-time polymorphisms. 1. Runtime polymorphism is implemented through virtual functions, allowing the correct method to be called dynamically at runtime. 2. Compilation-time polymorphism is implemented through function overloading and templates, providing higher performance and flexibility.

C polymorphismincludescompile-time,runtime,andtemplatepolymorphism.1)Compile-timepolymorphismusesfunctionandoperatoroverloadingforefficiency.2)Runtimepolymorphismemploysvirtualfunctionsforflexibility.3)Templatepolymorphismenablesgenericprogrammingfo

C polymorphismisuniqueduetoitscombinationofcompile-timeandruntimepolymorphism,allowingforbothefficiencyandflexibility.Toharnessitspowerstylishly:1)Usesmartpointerslikestd::unique_ptrformemorymanagement,2)Ensurebaseclasseshavevirtualdestructors,3)Emp
