Boost C++ Libraries

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transformed
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Syntax

Code

Pipe

rng | boost::adaptors::transformed(fun)

Function

boost::adaptors::transform(rng, fun)

  • Precondition: The value_type of the range is convertible to the argument type of fun.
  • Postcondition: For all elements x in the returned range, x is the result of fun(y) where y is the corresponding element in the original range.
  • Throws: Whatever the copy-constructor of fun might throw.
  • Range Category: Single Pass Range
  • Range Return Type: boost::transformed_range<decltype(rng)>
  • Returned Range Category: The range category of rng.

#include <boost/range/adaptor/transformed.hpp>
#include <boost/range/algorithm/copy.hpp>
#include <boost/assign.hpp>
#include <iterator>
#include <iostream>
#include <vector>

struct double_int
{
    typedef int result_type;
    int operator()(int x) const { return x * 2; }
};

int main(int argc, const char* argv[])
{
    using namespace boost::adaptors;
    using namespace boost::assign;

    std::vector<int> input;
    input += 1,2,3,4,5,6,7,8,9,10;

    boost::copy(
        input | transformed(double_int()),
        std::ostream_iterator<int>(std::cout, ","));

    return 0;
}

This would produce the output:

2,4,6,8,10,12,14,16,18,20,


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