关于数组：如何使用Java计算ArrayList模型的行和列

How to count raw and colomn for ArrayList Model with Java

我问一个问题，我有模型数组列表，但我想将模型数组列表中的值转换为或添加到Java中的ArrayList 2维中。？

我的代码：

Abc类：

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public class Abc {

private Integer value1;
private Integer value2;
private Integer value3;
private Integer value4;

public Abc(){
}

public Integer getValue1() {
return value1;
}

public void setValue1(Integer value1) {
this.value1 = value1;
}

public Integer getValue2() {
return value2;
}

public void setValue2(Integer value2) {
this.value2 = value2;
}

public Integer getValue3() {
return value3;
}

public void setValue3(Integer value3) {
this.value3 = value3;
}

public Integer getValue4() {
return value4;
}

public void setValue4(Integer value4) {
this.value4 = value4;
}
}

主要班级：

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public class Ebd {
public static void main (String [] args){
List<Abc> itemAbc = new ArrayList<Abc>();
Abc model1 = new Abc();
model1.setValue1(6);
model1.setValue2(4);
model1.setValue3(3);
model1.setValue4(5);
itemAbc.add(model1);

model1.setValue1(3);
model1.setValue2(1);
model1.setValue3(6);
model1.setValue4(4);
itemAbc.add(model1);
}
}

itemAbc => int a [] [] ..... ??

F = {{6,4,3,5}，{3,1,6,4}}

我想要矩阵：

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3

R = 6,4,3,5

3,1,6,4

您可以得到R(1,1)= 6.

如何将值数组列表itemAbc发送到数组2维？

谢谢。

相关讨论

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1. Following code will convert your list to two dimensional array.

private int[][] to2DArray(List<Abc> itemAbc){
int[][] a = null;
if(itemAbc!=null){
a = new int[itemAbc.size()][4];
int i = 0;
for(Abc abc : itemAbc){
a[i][0] = abc.getValue1();
a[i][1] = abc.getValue2();
a[i][2] = abc.getValue3();
a[i][3] = abc.getValue4();
i++;
}
}
return a;
}

2. You are missing initialization of Abc object after adding first object .

List<Abc> itemAbc = new ArrayList<Abc>();
Abc model1 = new Abc();
model1.setValue1(6);
model1.setValue2(4);
model1.setValue3(3);
model1.setValue4(5);
itemAbc.add(model1);
model1 =new Abc();// line you are missing.
model1.setValue1(3);
model1.setValue2(1);
model1.setValue3(6);
model1.setValue4(4);
itemAbc.add(model1);