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This article introduces the relevant knowledge of "what is the search content of C# regular expression string". In the operation of actual cases, many people will encounter such a dilemma. Next, let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

C # regular expression and string search 1. Introduction to regular expression

Regular expressions provide a powerful, flexible, and efficient way to process text.

The comprehensive pattern matching representation of regular expressions can quickly analyze large amounts of text to find specific character patterns; extract, edit, replace, or delete text substrings; or add extracted strings to the collection to generate reports.

Regular expressions are an indispensable tool for many applications that deal with strings such as HTML processing, log file analysis, and HTTP header analysis.

.net Framework regular expressions incorporate the most common features of other regular expression implementations and are designed to be compatible with Perl 5 regular expressions. .NET Framework regular expressions also include features that have not been provided in other implementations, and the .NET Framework regular expression classes are part of the base class library and can be used with any language or tool for the common language runtime.

C # regular expression and string search 2. String search

The regular expression language consists of two basic character types: literal (normal) text characters and metacharacters. It is the metacharacter group that provides processing power for regular expressions. Currently, all text editors have some search functions. You can usually open a dialog box and type the string you want to locate in one of the text boxes. If you want to replace at the same time, you can type a replacement string, such as notepad in the Windows operating system and document editors in the Office series.

This is the easiest way to search, and such problems can easily be solved with the String.Replace () method of the String class, but what if you need to identify a duplicate in the document? Writing a routine to select repetitive words from a String class is complex, and the language is appropriate at this time.

A general expression language is a language that can write search expressions. In this language, you can combine the text to be searched for, escape sequences, and other characters with a specific meaning in a document, such as the sequence\ b representing the beginning and end of a word (the boundary of a child), and if you want to represent the word you are looking for that begins with the character th, you can write a general expression\ bth (that is, the sequence character boundary is-tMuh).

If you want to search for all words that end in th, you can write th\ b (the sequence tmurh-word boundary). However, general expressions are much more complex than this; for example, a tool program (facility) that stores part of the text can be found in a search operation.

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