[英]Find substring in string with iterators
I have a substring defined by two iterators ( start
and end
). 我有一个由两个迭代器( start
和end
)定义的子字符串。 I need to check if this substring is present in another string. 我需要检查此子字符串是否存在于另一个字符串中。
Is there a standard library algorithm or string member I can use or adapt to do this without creating a whole new string object ( std::string(start, end)
) just for this purpose? 我是否可以使用标准标准的算法或字符串成员来执行此操作,而无需为此创建一个全新的字符串对象( std::string(start, end)
)?
eg 例如
struct Substring
{
std::string::const_iterator start, end;
};
auto found = std::contains(whole.begin(), whole.end(), substring.start, substring.end); // ???
bool found =
std::search(hay.begin(), hay.end(), needle.begin(), needle.end()) != hay.end();
You can use the std::string::find
method: 您可以使用std::string::find
方法:
auto found = (whole.find(&*substring.start, 0, substring.end - substring.start)
!= std::string::npos);
The advantage over std::search
is that std::find
works on strings and can be implemented using Boyer-Moore. 与std::search
相比,优点是std::find
可在字符串上运行,并且可以使用Boyer-Moore来实现。 Sadly, that is not how gcc's libstdc++ implements it. 可悲的是,这不是gcc的libstdc ++实现它的方式。
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