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Difference between revisions of "Template:cpp/container/erase2"

From cppreference.com
(Add example)
m (generalize)
Line 51: Line 51:
 
#include <iostream>
 
#include <iostream>
 
#include <numeric>
 
#include <numeric>
−
#include <vector>
+
#include <{{#switch:{{{1}}}|basic_string=string|{{{1}}}}}>
  
−
void print_vector(const std::vector<int>& v)
+
void print_container(const std::{{#switch:{{{1}}}|basic_string=string|{{{1}}}<char>}}& v)
 
{
 
{
 
     for (auto x : v) {
 
     for (auto x : v) {
Line 63: Line 63:
 
int main()
 
int main()
 
{
 
{
−
     std::vector<int> v(10);
+
     std::{{#switch:{{{1}}}|basic_string=string|{{{1}}}<char>}} cnt(10);
−
     std::iota(v.begin(), v.end(), 0);
+
     std::iota(cnt.begin(), cnt.end(), '0');
  
 
     std::cout << "Init:\n";
 
     std::cout << "Init:\n";
−
     print_vector(v);
+
     print_container(v);
  
−
     std::erase(v, 5);
+
     std::erase(v, '5');
−
     std::cout << "Erase 5:\n";
+
     std::cout << "Erase \'5\':\n";
−
     print_vector(v);
+
     print_container(v);
  
−
     std::erase_if(v, [](int x) { return x % 2 == 0; });
+
     std::erase_if(v, [](char x) { return (x - '0') % 2 == 0; });
 
     std::cout << "Erase all even numbers:\n";
 
     std::cout << "Erase all even numbers:\n";
−
     print_vector(v);
+
     print_container(v);
 
}
 
}
 
  | output=
 
  | output=

Revision as of 23:18, 3 October 2019

{{cpp/container/{{{1}}}/navbar}}

Defined in header [[cpp/header/{{{1}}}|<{{{1}}}>]]
template< ..., class U >
void erase(std::{{{1}}}<...>& c, const U& value);
 (1) (since C++20)
template< ..., class Pred >
void erase_if(std::{{{1}}}<...>& c, Pred pred);
 (2) (since C++20)
1) Erases all elements that compare equal to value from the container.
2) Erases all elements that satisfy the predicate pred from the container.

Contents

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). ​

Complexity

Linear.

Example

Run this code
#include <iostream>
#include <numeric>
#include <{{{1}}}>
 
void print_container(const std::{{{1}}}<char>& v)
{
    for (auto x : v) {
        std::cout << x << ' ';
    }
    std::cout << '\n';
}
 
int main()
{
    std::{{{1}}}<char> cnt(10);
    std::iota(cnt.begin(), cnt.end(), '0');
 
    std::cout << "Init:\n";
    print_container(v);
 
    std::erase(v, '5');
    std::cout << "Erase \'5\':\n";
    print_container(v);
 
    std::erase_if(v, [](char x) { return (x - '0') % 2 == 0; });
    std::cout << "Erase all even numbers:\n";
    print_container(v);
}

Output: 

Init:
0 1 2 3 4 5 6 7 8 9 
Erase 5:
0 1 2 3 4 6 7 8 9 
Erase all even numbers:
1 3 7 9


See also

 removes elements satisfying specific criteria
(function template) [edit]
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