[section:remove_if remove_if]

[heading Prototype]

``
template<
    class ForwardRange,
    class UnaryPredicate
    >
typename range_iterator<ForwardRange>::type
remove(ForwardRange& rng, UnaryPredicate pred);

template<
    class ForwardRange,
    class UnaryPredicate
    >
typename range_iterator<const ForwardRange>::type
remove(const ForwardRange& rng, UnaryPredicate pred);

template<
    range_return_value re,
    class ForwardRange,
    class UnaryPredicate
    >
typename range_return<ForwardRange,re>::type
remove(ForwardRange& rng, UnaryPredicate pred);

template<
    range_return_value re,
    class ForwardRange,
    class UnaryPredicate
    >
typename range_return<const ForwardRange,re>::type
remove(const ForwardRange& rng, UnaryPredicate pred);
``

[heading Description]

`remove_if` removes from `rng` all of the elements `x` for which `pred(x)` is `true`. The versions of `remove_if` that return an iterator, return an iterator `new_last` such that the range `[begin(rng), new_last)` contains no elements where `pred(x)` is `true`. The iterators in the range `[new_last, end(rng))` are dereferenceable, but the elements are unspecified.

[heading Definition]

Defined in the header file `boost/range/algorithm/remove_if.hpp`

[heading Requirements]

* `ForwardRange` is a model of the __forward_range__ Concept.
* `ForwardRange` is mutable.
* `UnaryPredicate` is a model of the `PredicateConcept`.
* `ForwardRange`'s value type is convertible to `UnaryPredicate`'s argument type.

[heading Complexity]

Linear. `remove_if` performs exactly `distance(rng)` applications of `pred`.

[endsect]