Pass multiple strings to the string::find function

问题

Is it possible to somehow pass multiple strings to the string::find function?

For example, to find a string I might use this:

str.find("a string");

What I'd like to do is something like this:

str.find("a string" || "another string" || "yet another string")

And have the function return the position of the first occurrence of any of the three strings.

Thanks for any suggestions.

回答1:

Not with std::string::find, but you could use std::find_if from <algorithm>:

std::string str("a string");
std::array<std::string, 3> a{"a string", "another string", "yet another string"};
auto it = std::find_if(begin(a), end(a),
                       [&](const std::string& s)
                       {return str.find(s) != std::string::npos; });
if (it != end(a))
{
    std::cout << "found";
}

回答2:

That is not possible but what you can do is:

auto is_there(std::string haystack, std::vector<std::string> needles) -> std::string::size_type {

  for(auto needle : needles ){
    auto pos = haystack.find(needle);
    if(pos != std::string::npos){
      return pos;
    }

  }  
  return std::string::npos;
}  

回答3:

Either call find multiple times or construct a regular expression from the strings that you want to find. C++11 has support for regular expressions in <regex>.

来源：https://stackoverflow.com/questions/19952155/pass-multiple-strings-to-the-stringfind-function