如何使用Java计算ArrayList模型的原始和列数
我问这个问题,我有模型数组列表,但我希望模型数组列表中的值在java中转换或添加到ArrayList 2维 我的代码: Abc类:如何使用Java计算ArrayList模型的原始和列数,java,arrays,arraylist,multidimensional-array,Java,Arrays,Arraylist,Multidimensional Array,我问这个问题,我有模型数组列表,但我希望模型数组列表中的值在java中转换或添加到ArrayList 2维 我的代码: Abc类: public class Abc { private Integer value1; private Integer value2; private Integer value3; private Integer value4; public Abc(){ } public Integer getValue1() {
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;
}
}
班长:
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);
}
}
你可以得到R(1,1)=6
如何将值数组列表项ABC发送到数组2维度
谢谢。1。下面的代码将把列表转换成二维数组。
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);
私有int[]to2DArray(列表项ABC){
int[]a=null;
如果(itemAbc!=null){
a=新的整数[itemAbc.size()][4];
int i=0;
用于(Abc:itemAbc){
a[i][0]=abc.getValue1();
a[i][1]=abc.getValue2();
a[i][2]=abc.getValue3();
a[i][3]=abc.getValue4();
i++;
}
}
返回a;
}
2.添加第一个对象后,缺少Abc对象的初始化。
List itemAbc=new ArrayList();
Abc模型1=新Abc();
模型1.setValue1(6);
模型1.设定值2(4);
模型1.设定值3(3);
模型1.设定值4(5);
项目ABC.add(模型1);
model1=新Abc();//你缺了一行。
模型1.setValue1(3);
模型1.设定值2(1);
模型1.设定值3(6);
模型1.设定值4(4);
项目ABC.add(模型1);
什么是Abc…?@YCF\u L Abc是classHi!您想如何决定将列表元素放在二维数组的哪个索引中?如果使用private list list=new ArrayList()代码>而不是类中的4个属性?可能重复
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);