Regular expressions library

 

C++

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Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Regular expressions library

Classes

basic_regex (C++11)

sub_match (C++11)

match_results (C++11)

Algorithms

regex_match (C++11)

regex_search (C++11)

regex_replace (C++11)

Iterators

regex_iterator (C++11)

regex_token_iterator (C++11)

Exceptions

regex_error (C++11)

Traits

regex_traits (C++11)

Constants

syntax_option_type (C++11)

match_flag_type (C++11)

error_type (C++11)

 

Defined in header <regex>

정규표현식 라이브러리는 일종의 소형언어로 문자열내에서 패턴매칭을 수행하기 위한 정규표현식 클래스를 제공합니다.

또한 정규표현식 라이브러리 내부에는 각종 알고리즘, 반복자, 예외, 타입 특징을 지원하는 유틸리티 클래스들을 제공하고 있습니다.

주요 클래스

이 클래스들은 정규표현식과 목표 문자열의 시퀀스에 대한 정규표현식의 매칭 결과가 캡슐화 되어 있습니다.

basic_regex (C++11)	regular expression object (class template)
sub_match (C++11)	identifies the sequence of characters matched by a sub-expression (class template)
match_results (C++11)	identifies one regular expression match, including all sub-expression matches (class template)

알고리즘

이 함수는 regex로 캡슐화된 정규표현식을 목표 문자열 시퀀스에 적용하는데 사용합니다.

regex_match (C++11)	attempts to match a regular expression to an entire character sequence (function template)
regex_search (C++11)	attempts to match a regular expression to any part of a character sequence (function template)
regex_replace (C++11)	replaces occurrences of a regular expression with formatted replacement text (function template)

반복자

regex 반복자는 시퀀스에서 발견한 정규표현식의 매칭의 모든 집합을 순회하는데 사용합니다.

regex_iterator (C++11)	iterates through all regex matches within a character sequence (class template)
regex_token_iterator (C++11)	iterates through the specified sub-expressions within all regex matches in a given string or through unmatched substrings (class template)

예외

정규 표현식 라이브러리에서 에러를 리포팅 하기위해 예외를 던지는데 사용하는 객체의 타입 정의하는 클래스 입니다.

regex_error (C++11)	reports errors generated by the regular expressions library (class)

특징

regex 특징 클래스는 regex의 지역화에 대해 캡슐화 하는데 사용합니다.

regex_traits (C++11)	provides metainformation about a character type, required by the regex library (class template)

Constants

Defined in namespace std::regex_constants
syntax_option_type (C++11)	general options controlling regex behavior (typedef)
match_flag_type (C++11)	options specific to matching (typedef)
error_type (C++11)	describes different types of matching errors (typedef)

Example

run this code

#include <iostream>
#include <iterator>
#include <string>
#include <regex>
 
int main()
{
    std::string s = "Some people, when confronted with a problem, think "
        "\"I know, I'll use regular expressions.\" "
        "Now they have two problems.";
 
    std::regex self_regex("REGULAR EXPRESSIONS",
            std::regex_constants::ECMAScript | std::regex_constants::icase);
    if (std::regex_search(s, self_regex)) {
        std::cout << "Text contains the phrase 'regular expressions'\n";
    }
 
    std::regex word_regex("(\\S+)");
    auto words_begin = 
        std::sregex_iterator(s.begin(), s.end(), word_regex);
    auto words_end = std::sregex_iterator();
 
    std::cout << "Found "
        << std::distance(words_begin, words_end)
        << " words\n";
 
    const int N = 6;
    std::cout << "Words greater than " << N << " characters:\n";
    for (std::sregex_iterator i = words_begin; i != words_end; ++i) {
        std::smatch match = *i;
        std::string match_str = match.str();
        if (match_str.size() > N) {
            std::cout << "  " << match_str << '\n';
        }
    }
 
    std::regex long_word_regex("(\\w{7,})");
    std::string new_s = std::regex_replace(s, long_word_regex, "[$&]");
    std::cout << new_s << '\n';
}

Output:

Text contains the phrase 'regular expressions'
Found 19 words
Words greater than 6 characters:
  people,
  confronted
  problem,
  regular
  expressions."
  problems.
Some people, when [confronted] with a [problem], think 
"I know, I'll use [regular] [expressions]." Now they have two [problems].