How to Efficiently Delete Elements from an std::vector by Index?

Deleting Elements from an std::vector by Index

In the realm of data manipulation, the std::vector container plays a crucial role in representing ordered sequences of elements. As you delve into complex algorithms and data transformations, you may encounter a scenario where you need to remove a specific element from your std::vector. Here's how to achieve this using the erase() function:

Deleting a Single Element:

To remove a single element at index n from your std::vector, you can employ the following technique:

std::vector<int> vec;

vec.push_back(6);
vec.push_back(-17);
vec.push_back(12);

// Deletes the second element (vec[1])
vec.erase(std::next(vec.begin()));

Deleting Multiple Elements:

For scenarios where you need to erase a range of elements, the erase() function offers you the flexibility to specify the starting and ending indices of the target elements. This allows you to efficiently remove multiple elements at once:

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

Understanding the erase() Function:

The erase() function operates on iterators, which are objects that represent positions within a container. The first parameter of erase() takes an iterator to the element you wish to remove, while the optional second parameter can specify an iterator to the element immediately after the last one you want to delete. This flexibility enables you to define the precise range of elements to be erased.

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