remove vector element c++ code example

Example 1: remove element by index from vector c++

// Deletes the second element (vec[1])
vec.erase(vec.begin() + 1);

// Deletes the second through third elements (vec[1], vec[2])
vec.erase(vec.begin() + 1, vec.begin() + 3);

Example 2: remove value from vector c++

#include <algorithm>
#include <vector>

// using the erase-remove idiom

std::vector<int> vec {2, 4, 6, 8};
int value = 8 // value to be removed
vec.erase(std::remove(vec.begin(), vec.end(), value), vec.end());

Example 3: delete from front in vector c++

// Deleting first element
vector_name.erase(vector_name.begin());

// Deleting xth element from start
vector_name.erase(vector_name.begin()+(x-1));

// Deleting from the last
vector_name.pop_back();

Example 4: remove element by index from vector c++

// Why not setup a lambda you can use again & again
auto removeByIndex = 
  []<class T>(std::vector<T> &vec, unsigned int index)
{
	// This is the meat & potatoes
  	vec.erase(vec.begin() + index);
};

// Then you can throw whatever vector at it you desire
std::vector<std::string> stringvec = {"Hello", "World"};
// Will remove index 1: "World"
removeByIndex(stringvec, 1);
// Vector of integers, we will use push_back
std::vector<unsigned int> intvec;
intvec.push_back(33);
intvec.push_back(66);
intvec.push_back(99);
// Will remove index 2: 99
removeByIndex(intvec, 2);

Example 5: how to delete an element in vector pair in cpp

#include <iostream>
#include <utility>
#include <vector>

using namespace std;


int main()
{
    vector< pair<int, int> > v;
    int N = 5;
    const int threshold = 2;
    for(int i = 0; i < N; ++i)
        v.push_back(make_pair(i, i));

    int i = 0;
    while(i < v.size())
        if (v[i].second > threshold)
            v.erase(v.begin() + i);
        else
            i++;

    for(int i = 0; i < v.size(); ++i)
        cout << "(" << v[i].first << ", " << v[i].second << ")\n";

    cout << "Done" << endl;
}

Example 6: vector erase specific element

template <typename T>
void remove(std::vector<T>& vec, size_t pos)
{
    std::vector<T>::iterator it = vec.begin();
    std::advance(it, pos);
    vec.erase(it);
}