std::erase, std::erase_if(std::inplace_vector) - cppreference.com (original) (raw)

Defined in header <inplace_vector>
template< class T, std::size_t N, class U = T > constexpr typename std::inplace_vector<T, N>::size_type erase( std::inplace_vector<T, N>& c, const U& value ); (1) (since C++26)
template< class T, std::size_t N, class Pred > constexpr typename std::inplace_vector<T, N>::size_type erase_if( std::inplace_vector<T, N>& c, Pred pred ); (2) (since C++26)

  1. Erases all elements that compare equal to value from the container c. Equivalent toauto it = std::remove(c.begin(), c.end(), value);
    auto r = std::distance(it, c.end());
    c.erase(it, c.end());
    return r;.

  2. Erases all elements that satisfy the predicate pred from the container c. Equivalent toauto it = std::remove_if(c.begin(), c.end(), pred);
    auto r = std::distance(it, c.end());
    c.erase(it, c.end());
    return r;.

[edit] Parameters

c - container from which to erase
value - value to be removed
pred - unary predicate which returns ​true if the element should be erased. The expression pred(v) must be convertible to bool for every argument v of type (possibly const) T, regardless of value category, and must not modify v. Thus, a parameter type of T&is not allowed, nor is T unless for T a move is equivalent to a copy(since C++11). ​

[edit] Return value

The number of erased elements.

[edit] Complexity

Linear.

[edit] Example

#include #include #include #include #include   int main() { std::inplace_vector<int, 10> v(10, 0); std::ranges::iota(v, 0); std::println("Initially, v = {}", v);   auto erased = std::erase(v, 3); std::println("After erase(v, 3), v = {}", v); assert(erased == 1);   erased = std::erase_if(v, [](int x) { return x % 2 == 0; }); std::println("After erasing all even numbers, v = {}", v); std::println("Erased even numbers: {}", erased);   std::inplace_vector<std::complex> nums{{2, 2}, {4, 2}, {4, 8}, {4, 2}}; std::erase(nums, {4, 2}); // since U = T, the value type can be ommited std::println("After erase {4, 2}, nums = {}", nums); }

Output:

Initially, v = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] After erase(v, 3), v = [0, 1, 2, 4, 5, 6, 7, 8, 9] After erasing all even numbers, v = [1, 5, 7, 9] Erased even numbers: 5 After erase {4, 2}, nums = [(2,2), (4,8)]

[edit] See also