The C++17 std::string_view has a constexpr substr() : https://en.cppreference.com/w/cpp/string/basic_string_view/substr While the absl version of substr() can not be used in a constexpr abseil-cpp/absl/strings/string_view.h Line 385 in 0...
在处理子串时,std::string::substr也需要进行拷贝和分配内存,而std::string_view::substr则不需要,在处理大文件解析时,性能优势非常明显。 平时代码中可以大规模使用的一个特性。其实对于string的争论一直没有停止过,很多人认为string是字节串而不是字符串,因为string是可以改变的,这一切争论到C++17可以停止了。strin...
#include <string_view>int main() { typedef std::size_t count_t, pos_t;constexpr std::string_view data{"ABCDEF"};std::cout << data.substr() << '\n'; // ABCDEF, 即 data[0, 5],为 [0, 6) std::cout << data.substr
constexpr string_view substr(size_type pos, size_type n = npos) const { return ABSL_PREDICT_FALSE(pos > length_) ? (base_internal::ThrowStdOutOfRange( "absl::string_view::substr"), string_view()) : string_view(ptr_ + pos, Min(n, length_ - pos)); ...
<cpp |string |basic string view constexprbasic_string_view substr(size_type pos=0, size_type count=npos)const; (since C++17) Returns a view of the substring[pos,pos+rlen), whererlenis the smaller ofcountandsize()-pos.
basic_string_view::empty Modifiers basic_string_view::remove_prefix basic_string_view::remove_suffix basic_string_view::swap Operations basic_string_view::to_stringbasic_string_view::operator basic_string basic_string_view::copy basic_string_view::substr ...
std::u16string_view(C++17)std::basic_string_view<char16_t> std::u32string_view(C++17)std::basic_string_view<char32_t> std::wstring_view(C++17)std::basic_string_view<wchar_t> std::hash<std::string_view>std::hash<std::wstring_view>std::hash<std::u8string_view>std::hash<std::...
string substr(int pos = 0,int n = npos) const;//返回pos开始的n个字符组成的字符串string的交换: void swap(string &s2); //交换当前字符串与s2的值 string类的查找函数: int find(char c, int pos = 0) const;//从pos开始查找字符c在当前字符串的位置int find(const char *s, int pos = 0...
();size_tdummy_len = TypeName<void>::fullname_intern().size() -4*multiple;size_ttarget_len = (fullname_intern().size() - dummy_len)/multiple;std::string_view rv = fullname_intern().substr(prefix_len, target_len);if(rv.rfind(' ') == rv.npos)returnrv;returnrv.substr(rv....
stringx=“abcdef”;i.e.x.substr(pos,n)x.substr(pos)x.substr()x.substr(2,3);//”cde”x.substr(2,100);//”cdef”x.substr(2);//“cdef”x.substr();//“abcdef”NOTE:std::string::npos表示串中字符的最大位置std::string::npos 7.Erase •x.erase(pos=0,n=npos)•x.clear()i...