std::erase,std::erase_if(std::vector)

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operator==operator<=> (C++20)
swap(std::vector)
erase(std::vector)erase_if(std::vector) (C++20)(C++20)

operator!=operator<operator>operator<=operator>=

(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)

Deduction guides(C++17)

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Defined in header`<vector>`
	(1)
template<class T,class Alloc,class U> constexprtypenamestd::vector<T, Alloc>::size_type erase(std::vector<T, Alloc>& c,const U& value);			(since C++20) (until C++26)
template<class T,class Alloc,class U= T> constexprtypenamestd::vector<T, Alloc>::size_type erase(std::vector<T, Alloc>& c,const U& value);			(since C++26)
template<class T,class Alloc,class Pred> constexprtypenamestd::vector<T, Alloc>::size_type erase_if(std::vector<T, Alloc>& c, Pred pred);		(2)	(since C++20)

1) Erases all elements that compare equal tovalue from the containerc. 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 predicatepred from the containerc. 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 expressionpred(v) must be convertible tobool for every argument`v` of type (possibly const)`T`, regardless ofvalue category, and must not modify`v`. Thus, a parameter type ofT&is not allowed, nor isT unless for`T` 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

Run this code

#include <complex>#include <iostream>#include <numeric>#include <string_view>#include <vector> void println(std::string_view comment,constauto& c){std::cout<< comment<<'[';bool first{true};for(constauto& x: c)std::cout<<(first? first=false,"":", ")<< x;std::cout<<"]\n";} int main(){std::vector<char> cnt(10);std::iota(cnt.begin(), cnt.end(),'0');    println("Initially, cnt = ", cnt);     std::erase(cnt,'3');    println("After erase '3', cnt = ", cnt); auto erased= std::erase_if(cnt,[](char x){return(x-'0')%2==0;});    println("After erase all even numbers, cnt = ", cnt);std::cout<<"Erased even numbers: "<< erased<<'\n'; std::vector<std::complex<double>> nums{{2,2},{4,2},{4,8},{4,2}};#ifdef __cpp_lib_algorithm_default_value_type        std::erase(nums,{4,2});#else        std::erase(nums,std::complex<double>{4,2});#endif    println("After erase {4, 2}, nums = ", nums);}

Output:

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

[edit]See also

removeremove_if	removes elements satisfying specific criteria (function template)[edit]
ranges::removeranges::remove_if (C++20)(C++20)	removes elements satisfying specific criteria (algorithm function object)[edit]