Thread: find_if

I have a vector of pair<string, int>. Now I want to detect if there's an item in the vector where first is equal to some other string.

I wonder if someone might be able to show how to do this with <algorithm> (and perhaps <boost/lambda>) without creating a separate functor for the find_if algorithm (as that would be used only in one place).

(Sorry, I've had some wine and can't seem to figure this one out )

Member access. Tricky business. Without testing, I think something like this ought to work.

Code:

#include <functional>  // equal_to
#include <algorithm>   // find_if
#include <string>   // string
#include <utility>   // pair
#include <vector>  // vector
#include <boost/bind.hpp>    // bind

// ...
typedef std::pair<std::string, int> si_pair;
typedef std::vector<si_pair> si_pair_vector;
si_pair_vector vec;
// ...

std::string needle = whatever();
si_pair_vector::iterator it = std::find_if(vec.begin(), vec.end(),
  boost::bind(std::equal_to<std::string>(),
    boost::bind(&si_pair::first, boost::_1), needle));

Thanks, this indeed works.