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

Defined in header
(1)
template< class CharT, class Traits, class Alloc, class U > constexpr typename std::basic_string<CharT, Traits, Alloc>::size_type erase( std::basic_string<CharT, Traits, Alloc>& c, const U& value ); (since C++20) (until C++26)
template< class CharT, class Traits, class Alloc, class U = CharT > constexpr typename std::basic_string<CharT, Traits, Alloc>::size_type erase( std::basic_string<CharT, Traits, Alloc>& c, const U& value ); (since C++26)
template< class CharT, class Traits, class Alloc, class Pred > constexpr typename std::basic_string<CharT, Traits, Alloc>::size_type erase_if( std::basic_string<CharT, Traits, Alloc>& c, Pred pred ); (2) (since C++20)

  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 = c.end() - it;
    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 = c.end() - it;
    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) CharT, regardless of value category, and must not modify v. Thus, a parameter type of CharT&is not allowed, nor is CharT unless for CharT a move is equivalent to a copy(since C++11). ​

[edit] Return value

The number of erased elements.

[edit] Complexity

Linear.

Notes

Feature-test macro Value Std Feature
__cpp_lib_algorithm_default_value_type 202403 (C++26) List-initialization for std::erase

[edit] Example

Possible output:

Initially, word = "startling" After erase 'l', word = "starting" After erase all 'a', 'r', and 't': "sing" Erased symbols count: 4 After erase {'g'}: "sin"

[edit] See also