Remove group of elements from list

Question

What is the best way, in terms of performance, to remove a list (a group of elements such as integers or strings) from another list, other than using for or foreach loops?

For example, is there a function that takes a list as a parameter and removes every element in it?, similar to List.AddRange(), which takes a list as a parameter and adds every element from it.

public class ListsManager : MonoBehaviour
{
    [SerializeField] private List<int> _list = new List<int>() { 1, 2, 3, 4, 5, 7, 8, 9, 10 };
    [SerializeField] private List<int> _listToRemove = new List<int>() { 1, 3, 5, 7, 9 };

    void Start()
    {
        for (int i = 0; i < _listToRemove.Count; i++)
        {
            _list.Remove(_listToRemove[i]);
        }
    }
}

Answer 1

To remove elements from one list using another list in C#, you can use the RemoveAll method with a lambda. It's clean and avoids manual loops. Here's an example:

using System.Collections.Generic;
using UnityEngine;

public class ListsManager : MonoBehaviour {

    [SerializeField]
    private List<int> _list = new List<int>() { 1, 2, 3, 4, 5, 7, 8, 9, 10 }; 

    [SerializeField]  
    private List<int> _listToRemove = new List<int>() { 3, 4, 7 }; 

    private void Start() { 

        _list.RemoveAll(item => _listToRemove.Contains(item)); 

        Debug.Log(string.Join(", ", _list));
        // Outputs: 1, 2, 5, 8, 9, 10 
    }
}