std::experimental::ranges:: find_first_of

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C++
Experimental
Ranges
Algorithms library
Non-modifying sequence operations
Modifying sequence operations
Partitioning operations
Sorting operations
Binary search operations
Set operations (on sorted ranges)
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Permutations
template < InputIterator I1, Sentinel < I1 > S1, ForwardIterator I2, Sentinel < I2 > S2,

class Proj1 = ranges:: identity , class Proj2 = ranges:: identity ,
IndirectRelation < projected < I1, Proj1 > ,
projected < I2, Proj2 >> Pred = ranges:: equal_to <> >
I1 find_first_of ( I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = Pred { } ,

Proj1 proj1 = Proj1 { } , Proj2 proj2 = Proj2 { } ) ;
(1) (ranges TS)
template < InputRange R1, ForwardRange R2,

class Proj1 = ranges:: identity , class Proj2 = ranges:: identity ,
IndirectRelation < projected < ranges:: iterator_t < R1 > , Proj1 > ,
projected < ranges:: iterator_t < R2 > , Proj2 >> Pred = ranges:: equal_to <> >
ranges:: safe_iterator_t < R1 > find_first_of ( R1 && r1, R2 && r2, Pred pred = Pred { } ,

Proj1 proj1 = Proj1 { } , Proj2 proj2 = Proj2 { } ) ;
(2) (ranges TS)
1) Searches the range [ first1 , last1 ) for any of the elements in the range [ first2 , last2 ) , after projecting the ranges with proj1 and proj2 respectively. The projected elements are compared using pred .
2) Same as (1) , but uses r1 as the first source range and r2 as the second source range, as if using ranges:: begin ( r1 ) as first1 , ranges:: end ( r1 ) as last1 , ranges:: begin ( r2 ) as first2 , and ranges:: end ( r2 ) as last2 .

Parameters

first1, last1 - the range of elements to examine
r1 - the range of elements to examine
first2, last2 - the range of elements to search for
r2 - the range of elements to search for
pred - predicate to use to compare the projected elements with
proj1 - projection to apply to the elements in the first range
proj2 - projection to apply to the elements in the second range

Return value

Iterator to the first element in the range [ first1 , last1 ) that is equal to an element from the range [ first2 , last2 ) after projection. If no such element is found, an iterator comparing equal to last1 is returned.

Complexity

At most (S * N) applications of the predicate and each projection, where S = distance ( last2 - first2 ) and N = last1 - first1 .

Possible implementation 

template<InputIterator I1, Sentinel<I1> S1, ForwardIterator I2, Sentinel<I2> S2,
         class Proj1 = ranges::identity, class Proj2 = ranges::identity,
         IndirectRelation<projected<I1, Proj1>, 
                          projected<I2, Proj2>> Pred = ranges::equal_to<>>
I1 find_first_of(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = Pred{},
                 Proj1 proj1 = Proj1{}, Proj2 proj2 = Proj2{})
{
    for (; first1 != last1; ++first1)
        for (ForwardIt it = first2; it != last2; ++it)
            if (ranges::invoke(pred, ranges::invoke(proj1, *first1),
                                     ranges::invoke(proj2, *it)))
                return first1;
    return first1;
}

Example

This section is incomplete
Reason: no example

See also

searches for any one of a set of elements
(function template)
finds the first element satisfying specific criteria
(function template)
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