transform

Description

For a sequence seq and function object or function pointer f, transform returns a new sequence with elements created by applying f(e) to each element of e of seq.

Unary version synopsis

template<
    typename Sequence,
    typename F
    >
typename result_of::transform<Sequence const, F>::type transform(
    Sequence const& seq, F f);

Table 1.75. Parameters

Parameter	Requirement	Description
`seq`	A model of Forward Sequence	Operation's argument
`f`	`f(e)` is a valid expression for each element `e` of `seq`. `boost::result_of<F(E)>::type` is the return type of `f` when called with a value of each element type `E`.	Transformation function

Expression Semantics

transform(seq, f);

Return type: A model of Forward Sequence

Semantics: Returns a new sequence, containing the return values of f(e) for each element e within seq.

Binary version synopsis

template<
    typename Sequence1,
    typename Sequence2,
    typename F
    >
typename result_of::transform<Sequence1 const, Sequence2 const, F>::type transform(
    Sequence1 const& seq1, Sequence2 const& seq2, F f);

Table 1.76. Parameters

Parameter	Requirement	Description
`seq1`	A model of Forward Sequence	Operation's argument
`seq2`	A model of Forward Sequence	Operation's argument
`f`	`f(e1,e2)` is a valid expression for each pair of elements `e1` of `seq1` and `e2` of `seq2`. `boost::result_of<F(E1,E2)>::type` is the return type of `f` when called with elements of type `E1` and `E2`	Transformation function

Return type: A model of Forward Sequence.

Semantics: Returns a new sequence, containing the return values of f(e1, e2) for each pair of elements e1 and e2 within seq1 and seq2 respectively.

Complexity

Constant. Returns a view which is lazily evaluated.

Header

#include <boost/fusion/algorithm/transformation/transform.hpp>
#include <boost/fusion/include/transform.hpp>

Example

struct triple
{
    typedef int result_type;

    int operator()(int t) const
    {
        return t * 3;
    };
};
...
assert(transform(make_vector(1,2,3), triple()) == make_vector(3,6,9));