Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is an older version of Boost and was released in 2023. The current version is 1.89.0.

filter

filter

Description

Returns the result type of filter given the sequence type and type to retain.

Synopsis

template<
    typename Sequence,
    typename T
    >
struct filter
{
    typedef unspecified type;
};

Table 1.87. Parameter

Parameter	Requirement	Description
`Sequence`	A model of Forward Sequence	Operation's argument
`T`	Any type	Type to retain

Expression Semantics

result_of::filter<Sequence, T>::type

Return type:

A model of Forward Sequence.
A model of Associative Sequence if Sequence implements the Associative Sequence model.

Semantics: Returns a sequence containing the elements of Sequence that are of type T. Equivalent to result_of::filter_if<Sequence, boost::is_same<mpl::_, T> >::type.

Complexity

Constant.

Header

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