使arraylist等于另一个arraylist java

我有1d临时arraylist和2d原始arraylist，我在循环期间更新了临时arraylist，在循环结束时，我需要使原始arraylist等于临时arraylist的内容，如下所示：

while(!Front.get(front).isEmpty()){
        Q.clear();
        for(int i=0;i<Front.get(front).size();i++){
            if(!Individual_Dominate.get(Front.get(front).get(i)).isEmpty()){
                for(int j=0;j<Individual_Dominate.get(Front.get(front).get(i)).size();j++){
                    Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]=Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]-1;
                    if(Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]==0){
                        Solutions_to_arrange[Individual_Dominate.get(Front.get(front).get(i)).get(j)][Input.General_Inputs.Num_objectives+Input.General_Inputs.Num_Of_Ppes]=front+1;
                        Q.add(Individual_Dominate.get(Front.get(front).get(i)).get(j));
                    }
                }
            }
        }
        front++;
        Front.get(front)=Q // How to do this step
    }

我知道有像这样的方法

Front.get(front) = new ArrayList<Object>(Q);

或

但不确定这些方法是否合适，因为所有这些方法都会给我一份列表的副本，而不是它的所有元素。因此，如果我更改复制列表中的一个元素，它也将在原始列表中更改

更新 我提出了这个解决方案，有何评论

front++;
for(int i=0;i<Q.size();i++)
        Front.get(front).add(Q.get(i));
    }

我想这会管用的

while(!Front.get(front).isEmpty()){
        Q.clear();
        for(int i=0;i<Front.get(front).size();i++){
            if(!Individual_Dominate.get(Front.get(front).get(i)).isEmpty()){
                for(int j=0;j<Individual_Dominate.get(Front.get(front).get(i)).size();j++){
                    Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]=Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]-1;
                    if(Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]==0){
                        Solutions_to_arrange[Individual_Dominate.get(Front.get(front).get(i)).get(j)][Input.General_Inputs.Num_objectives+Input.General_Inputs.Num_Of_Ppes]=front+1;
                        Q.add(Individual_Dominate.get(Front.get(front).get(i)).get(j));
                    }
                }
            }
        }
    front++;
        for(int i=0;i<Q.size();i++)
        Front.get(front).add(Q.get(i));
    }

 import java.util.ArrayList;

 public class Main {

    public static void main(String[] args) {

        ArrayList<Integer> array = new ArrayList<Integer>();
        ArrayList<Integer> array1 = new ArrayList<Integer>();

        //supposedly you have ArrayList array = [1, 2, 3];

        for(int i : array) {
            array1.add(array.get(i));
        }

        System.out.print(array1);

        // output will give you [1, 2, 3]

这会奏效的

while(!Front.get(front).isEmpty()){
        Q.clear();
        for(int i=0;i<Front.get(front).size();i++){
            if(!Individual_Dominate.get(Front.get(front).get(i)).isEmpty()){
                for(int j=0;j<Individual_Dominate.get(Front.get(front).get(i)).size();j++){
                    Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]=Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]-1;
                    if(Individual_Number[Individual_Dominate.get(Front.get(front).get(i)).get(j)]==0){
                        Solutions_to_arrange[Individual_Dominate.get(Front.get(front).get(i)).get(j)][Input.General_Inputs.Num_objectives+Input.General_Inputs.Num_Of_Ppes]=front+1;
                        Q.add(Individual_Dominate.get(Front.get(front).get(i)).get(j));
                    }
                }
            }
        }
    front++;
        for(int i=0;i<Q.size();i++)
        Front.get(front).add(Q.get(i));
    }

 import java.util.ArrayList;

 public class Main {

    public static void main(String[] args) {

        ArrayList<Integer> array = new ArrayList<Integer>();
        ArrayList<Integer> array1 = new ArrayList<Integer>();

        //supposedly you have ArrayList array = [1, 2, 3];

        for(int i : array) {
            array1.add(array.get(i));
        }

        System.out.print(array1);

        // output will give you [1, 2, 3]

---

你怎么换双人间？它不会改变它。。。您正在处理拒绝使用objects/OOP的问题。不要把所有东西都扔进列表/集合中。