How do I remove an element from a 2D vector in C++?

How do I remove an element from a 2D vector in C++?

You can remove an element from a 2D vector in C++ using the erase method. First, locate the row and then the column index of the element you want to remove.

Can you show me a code example?

Sure! Here's a simple example:

#include <iostream>
#include <vector>

int main() {
    std::vector<std::vector<int>> vec = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
    int row = 1; // Row to remove from
    int col = 1; // Column to remove
    vec[row].erase(vec[row].begin() + col);
    
    // Print the updated vector
    for (const auto& r : vec) {
        for (const auto& c : r) {
            std::cout << c << " ";
        }
        std::cout << std::endl;
    }
}

This will remove the element at position (1, 1), which is '5'.

What if I want to remove an entire row?

To remove an entire row, you can use the erase method on the outer vector. For example:

vec.erase(vec.begin() + row);

This will remove the specified row from the 2D vector.

Thanks! Is there a way to check if an element exists before removing it?

Yes, you can use a loop to check if the element exists in the vector before attempting to remove it. You can iterate through the vector and use a condition to find the element.