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法律研究Java 程式按屬性對自定義物件的 ArrayList 排序
在本文中，我們將瞭解如何按屬性對自定義物件的 arrayList 排序。ArrayList 類擴充套件了 AbstractList 並實現了 List 介面。ArrayList 支援按需增長的動態陣列。
建立具有初始大小的陣列列表。超過此大小時，該集合將自動擴大。移除物件時，陣列可能會縮小。
以下是同樣的演示 −
假設我們的輸入是 −
The list is defined as Java Scala Python Mysql
期望的輸出是 −
The list after sorting values: Java Mysql Python Scala
演算法
Step 1 - START Step 2 - Declare namely Step 3 - Define the values. Step 4 - Use the ‘sort’ method to sort the list. Step 5 - Use the ‘compareTo’ method to compare properties of the list. Step 6 - Use the ‘add’ method to add new values to the list. Step 7 - In the main method, create an array list, and invoke the ‘sort’ method. Step 8 - Display the result Step 9 - Stop
示例 1
在這裡，我們將所有操作繫結在一起，置於“main”函式之下。
import java.util.*;
class CustomObject {
private String custom_property;
public CustomObject(String property){
this.custom_property = property;
}
public String get_custom_property(){
return this.custom_property;
}
}
public class Demo {
public static void print(ArrayList<CustomObject> input_list){
for (CustomObject object : input_list) {
System.out.println(object.get_custom_property());
}
}
public static void sort(ArrayList<CustomObject> input_list){
input_list.sort((object_1, object_2)
-> object_1.get_custom_property().compareTo(
object_2.get_custom_property()));
}
public static void add(ArrayList<CustomObject> input_list){
input_list.add(new CustomObject("Java"));
input_list.add(new CustomObject("Scala"));
input_list.add(new CustomObject("Python"));
input_list.add(new CustomObject("Mysql"));
}
public static void main(String[] args){
System.out.println("Required packages have been imported");
ArrayList<CustomObject> input_list = new ArrayList<>();
add(input_list);
System.out.println("The list is defined as ");
print(input_list);
sort(input_list);
System.out.println("\nThe list after sorting values: ");
print(input_list);
}
}輸出
Required packages have been imported The list is defined as Java Scala Python Mysql The list after sorting values: Java Mysql Python Scala
示例 2
在這裡，我們將操作封裝到函式中，展示面向物件程式設計。
import java.util.*;
class CustomObject {
private String custom_property;
public CustomObject(String property){
this.custom_property = property;
}
public String get_custom_property(){
return this.custom_property;
}
}
public class Demo {
public static void main(String[] args){
System.out.println("Required packages have been imported");
ArrayList<CustomObject> input_list = new ArrayList<>();
input_list.add(new CustomObject("Java"));
input_list.add(new CustomObject("Scala"));
input_list.add(new CustomObject("Python"));
input_list.add(new CustomObject("Mysql"));
System.out.println("The number is defined as ");
for (CustomObject object : input_list) {
System.out.println(object.get_custom_property());
}
input_list.sort((object_1, object_2)
-> object_1.get_custom_property().compareTo(
object_2.get_custom_property()));
System.out.println("\nThe list after sorting values: ");
for (CustomObject object : input_list) {
System.out.println(object.get_custom_property());
}
}
}輸出
Required packages have been imported The number is defined as Java Scala Python Mysql The list after sorting values: Java Mysql Python Scala
更新日期： 30-Mar-2022
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