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();   } }