thrust::remove

Defined in thrust/remove.h

template<typename DerivedPolicy, typename ForwardIterator, typename T> ForwardIterator thrust::remove(const thrust::detail::execution_policy_base<DerivedPolicy> &exec, ForwardIterator first, ForwardIterator last, const T &value)

remove removes from the range [first, last) all elements that are equal to value. That is, remove returns an iterator new_last such that the range [first, new_last) contains no elements equal to value. The iterators in the range [new_first,last) are all still dereferenceable, but the elements that they point to are unspecified. remove is stable, meaning that the relative order of elements that are not equal to value is unchanged.

The algorithm’s execution is parallelized as determined by exec.

The following code snippet demonstrates how to use remove to remove a number of interest from a range using the thrust::host execution policy for parallelization:

#include <thrust/remove.h>
#include <thrust/execution_policy.h>
...
const int N = 6;
int A[N] = {3, 1, 4, 1, 5, 9};
int *new_end = thrust::remove(A, A + N, 1);
// The first four values of A are now {3, 4, 5, 9}
// Values beyond new_end are unspecified

See also

remove_if

See also

remove_copy

See also

remove_copy_if

Note

The meaning of “removal” is somewhat subtle. remove does not destroy any iterators, and does not change the distance between first and last. (There’s no way that it could do anything of the sort.) So, for example, if V is a device_vector, remove(V.begin(), V.end(), 0) does not change V.size(): V will contain just as many elements as it did before. remove returns an iterator that points to the end of the resulting range after elements have been removed from it; it follows that the elements after that iterator are of no interest, and may be discarded. If you are removing elements from a Sequence, you may simply erase them. That is, a reasonable way of removing elements from a Sequence is S.erase(remove(S.begin(), S.end(), x), S.end()).

Parameters

exec – The execution policy to use for parallelization.
first – The beginning of the range of interest.
last – The end of the range of interest.
value – The value to remove from the range [first, last). Elements which are equal to value are removed from the sequence.

Template Parameters

DerivedPolicy – The name of the derived execution policy.
ForwardIterator – is a model of Forward Iterator, and ForwardIterator is mutable.
T – is a model of Equality Comparable, and objects of type T can be compared for equality with objects of ForwardIterator's value_type.

Returns

A ForwardIterator pointing to the end of the resulting range of elements which are not equal to value.