Erasing a vector element by key

Question

ive defined the following and filled it with elements:

vector <vector<double> > my_vector;

but i want a delete an element with a specific key...

my_vector.erase(int(specific_key));

but it doesnt allow me. how would i properly dispose of the elements assigned to that key properly?

Answer 1

Assuming by specific_key you mean the element at that position in the vector:

my_vector.erase(my_vector.begin() + specific_key);

Would be the "most correct" answer.

If you meant to delete the element that matches specific_key (which will have to be of type vector<double> in the given example:

my_vector.erase(find(my_vector.begin(), my_vector.end(), specific_key));

Answer 2

erase takes in an iterator as argument.

You can do

my_vector.erase (my_vector.begin() + specific_key);

You can also pass in a range

my_vector.erase (my_vector.begin(), my_vector.begin() + 2);

One thing that you should note is that the size of the vector also gets reduced.

Answer 3

The erase method takes iterators as their argument.

Example

Answer 4

If Specific key is not position and say its some data in vector, then one has to iterate vector for that data and erase particular iterator.