std::erase,std::erase_if(std::basic_string)

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[edit]

Strings library

Classes
basic_string
basic_string_view (C++17)
char_traits

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std::basic_string

Member functions
basic_string::basic_string
basic_string::~basic_string
basic_string::operator=
basic_string::assign
basic_string::assign_range (C++23)
basic_string::get_allocator
Element access
basic_string::at
basic_string::operator[]
basic_string::front (DR*)
basic_string::back (DR*)
basic_string::data
basic_string::c_str
basic_string::operator basic_string_view (C++17)
Iterators
basic_string::beginbasic_string::cbegin (C++11)
basic_string::endbasic_string::cend (C++11)
basic_string::rbeginbasic_string::crbegin (C++11)
basic_string::rendbasic_string::crend (C++11)
Search
basic_string::find
basic_string::rfind
basic_string::find_first_of
basic_string::find_first_not_of
basic_string::find_last_of
basic_string::find_last_not_of

Modifiers
basic_string::clear
basic_string::insert
basic_string::insert_range (C++23)
basic_string::erase
basic_string::push_back
basic_string::pop_back (DR*)
basic_string::append
basic_string::append_range (C++23)
basic_string::operator+=
basic_string::replace
basic_string::replace_with_range (C++23)
basic_string::copy
basic_string::resize
basic_string::resize_and_overwrite (C++23)
basic_string::swap
Capacity
basic_string::empty
basic_string::sizebasic_string::length
basic_string::max_size
basic_string::reserve
basic_string::capacity
basic_string::shrink_to_fit (DR*)
Operations
basic_string::compare
basic_string::starts_with (C++20)
basic_string::ends_with (C++20)
basic_string::contains (C++23)
basic_string::substr

swap(std::basic_string)

erase(std::basic_string)erase_if(std::basic_string)

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

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

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

Numeric conversions

stoistolstoll (C++11)(C++11)(C++11)
stoulstoull (C++11)(C++11)

stofstodstold (C++11)(C++11)(C++11)
to_string (C++11)
to_wstring (C++11)

Literals

operator""s

(C++14)

Helper classes

hash<std::basic_string>

(C++11)

Deduction guides(C++17)

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Defined in header`<string>`
	(1)
template<class CharT,class Traits,class Alloc,class U> constexprtypenamestd::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> constexprtypenamestd::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> constexprtypenamestd::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 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)`CharT`, regardless ofvalue category, and must not modify`v`. Thus, a parameter type ofCharT&is not allowed, nor isCharT 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

Run this code

#include <iomanip>#include <iostream>#include <string> int main(){std::string word{"startling"};std::cout<<"Initially, word = "<<std::quoted(word)<<'\n'; std::erase(word,'l');std::cout<<"After erase 'l': "<<std::quoted(word)<<'\n'; auto erased=std::erase_if(word,[](char x){return x=='a' or x=='r' or x=='t';}); std::cout<<"After erase all 'a', 'r', and 't': "<<std::quoted(word)<<'\n';std::cout<<"Erased symbols count: "<< erased<<'\n'; #if __cpp_lib_algorithm_default_value_typestd::erase(word,{'g'});std::cout<<"After erase {'g'}: "<<std::quoted(word)<<'\n';#endif}

Possible output:

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

[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]