没有躲过的坑--正则表达式截取字符串

工程中，需要从字符串中匹配出以:开头，并以:结束的字符串。

Google还是百度，很多C++的正则表达式都是通过st::tr1或boost库中使用的，但是我们仅仅用一个小小的功能，就用一个库不是很好的办法。

对的，之前我的博客已经介绍了C++11的新特性-正则表达式。

所以可以不使用其他的库，来完成任务：

std::vector<string> all_sub_string = {};std::string all_string = "12:wo:sfd:wom::sdf";std::regex e(":[a-z0-9_+-]+:");//正则规则const std::sregex_token_iterator end;for (std::sregex_token_iterator i(all_string .begin(), all_string .end(), e); i != end; ++i){    all_sub_string .push_back(*i);}

你可能会迷惑，什么是sregex_token_iterator？
不要着急，sregex_token_iterator其实就是字符串 regex_token_iterator 的类型定义。

typedef regex_token_iterator<string::const_iterator> sregex_token_iterator;

上面的方法很简单，就像使用迭代器一样。

其实regex还有其他的查找方法，现在介绍一下regex_search:
Returns whether some sub-sequence in the target sequence (the subject) matches the regular expression rgx (the pattern). The target sequence is either s or the character sequence between first and last, depending on the version used.

直接上代码：

// regex_search example#include <iostream>#include <string>#include <regex>int main (){  std::string s ("this subject has a submarine as a subsequence");  std::smatch m;  std::regex e ("\\b(sub)([^ ]*)");   // matches words beginning by "sub"  std::cout << "Target sequence: " << s << std::endl;  std::cout << "Regular expression: /\\b(sub)([^ ]*)/" << std::endl;  std::cout << "The following matches and submatches were found:" << std::endl;  while (std::regex_search (s,m,e)) {    for (auto x:m) std::cout << x << " ";    std::cout << std::endl;    s = m.suffix().str();  }  return 0;}

输出：

Target sequence: this subject has a submarine as subsequenceRegular expression: /\b(sub)([^ ]*)/The following matches and submatches were found:subject sub jectsubmarine sub marinesubsequence sub sequence