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| Sequence | ||||
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(C++26) | ||||
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| Associative | ||||
| Unordered associative | ||||
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| Adaptors | ||||
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(C++23) | ||||
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| Views | ||||
(C++20) | ||||
(C++23) | ||||
| Tables | ||||
| Iterator invalidation | ||||
| Member function table | ||||
| Non-member function table |
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Defined in header <unordered_set> | ||
template<class Key,class Hash,class KeyEqual,class Alloc, class Pred> | (since C++20) (constexpr since C++26) | |
Erases all elements that satisfy the predicatepred fromc.
Equivalent to
auto old_size= c.size();for(auto first= c.begin(), last= c.end(); first!= last;){if(pred(*first)) first= c.erase(first);else++first;}return old_size- c.size();
Contents |
| c | - | container from which to erase |
| pred | - | predicate that returnstrue if the element should be erased |
The number of erased elements.
Linear.
#include <iostream>#include <unordered_set> void println(auto rem,constauto& container){std::cout<< rem<<'{';for(char sep[]{0,' ',0};constauto& item: container)std::cout<< sep<< item,*sep=',';std::cout<<"}\n";} int main(){std::unordered_set data{3,3,4,5,5,6,6,7,2,1,0}; println("Original:\n", data); auto divisible_by_3=[](constauto& x){return(x%3)==0;}; constauto count=std::erase_if(data, divisible_by_3); println("Erase all items divisible by 3:\n", data);std::cout<< count<<" items erased.\n";}
Possible output:
Original:{0, 1, 2, 7, 6, 5, 4, 3}Erase all items divisible by 3:{1, 2, 7, 5, 4}3 items erased.| removes elements satisfying specific criteria (function template)[edit] | |
(C++20)(C++20) | removes elements satisfying specific criteria (algorithm function object)[edit] |
