java数组的怎删改查

Posted 2020-06-17

import java.util.List;  
import java.util.ArrayList;  
import java.util.Set;  
import java.util.HashSet;  
public class lzwCode {  
  
    public static void main(String [] args) {  
        testA();  
        System.out.println("===========================");  
        testB();  
        System.out.println("===========================");  
        testC();  
    }  
  
    //去掉数组中重复的值  
    public static void testA() {  
        String [] str = {"Java", "C++", "php", "C#", "Python", "C++", "Java"};  
        for (String elementA:str ) {  
            System.out.print(elementA + " ");  
        }  
        List<String> list = new ArrayList<String>();  
        for (int i=0; i<str.length; i++) {  
            if(!list.contains(str[i])) {  
                list.add(str[i]);  
            }  
        }  
        /* 
        Set<String> set = new HashSet<String>(); 
        for (int i=0; i<str.length; i++) { 
            set.add(str[i]); 
        } 
        String[] newStr =  set.toArray(new String[1]);  
        */  
        System.out.println();  
        String[] newStr =  list.toArray(new String[1]); //返回一个包含所有对象的指定类型的数组   
        for (String elementB:newStr ) {  
            System.out.print(elementB + " ");  
        }  
        System.out.println();  
    }  
  
    //删除数组中其中一个元素  
    public static void testB() {  
        String [] str = {"Java", "C++", "Php", "C#", "Python"};  
        for (String elementA:str ) {  
            System.out.print(elementA + " ");  
        }  
        //删除php  
        List<String> list = new ArrayList<String>();  
        for (int i=0; i<str.length; i++) {  
            list.add(str[i]);  
        }  
        list.remove(2); //list.remove("Php")   
        System.out.println();  
        String[] newStr =  list.toArray(new String[1]); //返回一个包含所有对象的指定类型的数组   
        for (String elementB:newStr ) {  
            System.out.print(elementB + " ");  
        }     
        System.out.println();  
    }  
  
    //在数组中增加一个元素  
    public static void testC() {  
        String [] str = {"Java", "C++", "Php", "C#", "Python"};  
        for (String elementA:str ) {  
            System.out.print(elementA + " ");  
        }  
        //增加ruby  
        List<String> list = new ArrayList<String>();  
        for (int i=0; i<str.length; i++) {  
            list.add(str[i]);  
        }  
        list.add(2, "ruby"); //list.add("ruby")   
        System.out.println();  
        String[] newStr =  list.toArray(new String[1]); //返回一个包含所有对象的指定类型的数组   
        for (String elementB:newStr ) {  
            System.out.print(elementB + " ");  
        }     
        System.out.println();  
    }  
}