c++ 去除字符串首尾的空白字符

c++ 去除字符串首尾的空白字符

• ​​方法一使用find_first_not_of和find_last_not_of​​
• ​​方法二使用正则表达式(c++11)​​
• ​​测试​​
• ​​测试结果​​

方法一使用find_first_not_of和find_last_not_of

/**
 * @brief Trimmed  去掉首尾 空格白
 * @param str
 */
void Trimmed(std::string& str) {
    str.erase(0, str.find_first_not_of(" \r\n\t\v\f"));
    str.erase(str.find_last_not_of(" \r\n\t\v\f") + 1);
//    std::cout << "Trimmed [" << str << "]" << std::endl;
}

方法二使用正则表达式(c++11)

/**
 * @brief Trimmed_Regex 正则表达式 去字符串首尾的 空白 c++ 11
 * @param str
 */
void Trimmed_Regex(std::string& str) {
    std::regex e("([\\S].*[\\S])");
    str = std::regex_replace (str,e,"$1",std::regex_constants::format_no_copy);
//    std::cout << "Trimmed_Regex [" << str << "]" << std::endl;
    //std::cout << "Trimmed_Regex [" << std::regex_replace (str,e,"$2") << "]" << std::endl;
}

测试

int main() {
    //std::string str ("there is a subsequence in the string\n");
    //     std::regex e ("\\b(sub)([^ ]*)");   // matches words beginning by "sub"

    //     // using string/c-string (3) version:
    //     std::cout << std::regex_replace (s,e,"sub-$2");

    //     // using range/c-string (6) version:

    //     std::cout << result;

    //     // with flags:
    //     std::cout << std::regex_replace (s,e,"$1 and $2",std::regex_constants::format_no_copy);
    //     std::cout << std::endl;

    clock_t start;

    std::string str = "\r\n   \t\v\f   {   Test 123 78927849……&*%&*&*（【】）代收款     } \t\v\f   \r\n";

    std::cout << "[" << str << "]" << std::endl;

    start = clock();
    Trimmed_Regex(str);
    std::cout << clock() - start << " Trimmed_Regex [" << str << "]" << std::endl;

    start = clock();
    Trimmed(str);
    std::cout << clock() - start << " Trimmed [" << str << "]" << std::endl;
    //     std::string result;
    //     std::regex_replace (std::back_inserter(result), str.begin(), str.end(), e, "");
    //    std::cout << "[" << result << "]" << std::endl;
    return 0;
}

测试结果