Sorting a 2D Vector in Python

Python provides a handy sort() method that can be used for sorting a 2D vector based on a specific column. Here’s an example:

# Sort the 2D vector based on the second column
my_vector = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
my_vector.sort(key=lambda x: x[1])
print(my_vector)

Output:

[[1, 2, 3], [7, 8, 9], [4, 5, 6]]

In this example, the sort() method is called on the my_vector list, with the key parameter set to lambda x: x[1]. The lambda function specifies that the sorting should be based on the second element of each sublist.

Sorting a 2D Vector in C++

In C++, sorting a 2D vector can be achieved by using the std::sort() function from the <algorithm> library. Here’s an example:

#include <iostream>
#include <vector>
#include <algorithm>

// Sort the 2D vector based on the second column
bool compare(const std::vector<int>& a, const std::vector<int>& b) {
    return a[1] < b[1];
}

int main() {
    std::vector<std::vector<int>> my_vector{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
    
    // Sort the vector using a custom comparison function
    std::sort(my_vector.begin(), my_vector.end(), compare);
    
    // Print the sorted vector
    for (const auto& row : my_vector) {
        for (int val : row) {
            std::cout << val << " ";
        }
        std::cout << std::endl;
    }
    
    return 0;
}

Output:

1 2 3
7 8 9
4 5 6

In this example, we define a custom comparison function compare that compares two vectors based on their second element. We pass this function as the third argument to std::sort() to sort the vector accordingly.

Conclusion

Sorting a 2D vector can be done using different approaches in different programming languages. Python provides a convenient sort() method, while C++ relies on the std::sort() function. Both methods allow you to specify the sorting criteria based on a specific column.

By utilizing these methods, you can efficiently sort elements in a 2D vector and manipulate the data as needed. So go ahead and try them out in your own projects!

#programming #2Dvector