Java中对Array数组的常用操作
import java.util.*;
public class ArrayPrint {
public static void main(String[] args){
//声明数组
String [] arr;
int arr1[];
//初始化数组
int arr2[]=new int[]{1,2,3,4,5};
String[] array1={"马超","马云","关羽","刘备","张飞"};
String[] array2=new String[]{"黄渤","张艺兴","孙红雷","小猪","牙哥","黄磊"};
String[] array=new String;
//查看数组的长度
int length=array1.length;
System.out.println("length："+array1.length);
//输出数组
System.out.println(array1); //结果：[Ljava.lang.String;@32f22097
System.out.println("arr2:"+Arrays.toString(arr2));
//遍历数组
for (int i = 0; i < array1.length; i++) {
System.out.println(array1);
}
//int数组转成string数组
int[]array3={1,2,3,4,5,6,7,8,9,0};
String arrStrings=Arrays.toString(array3);
System.out.println("arrStrings:"+arrStrings);
//从array中创建arraylist
ArrayList <String> arrayList=new ArrayList<String>(Arrays.asList(array1));
System.out.println("arrayList:"+arrayList);
//数组中是否包含某一个值
String a="马超";
if (Arrays.asList(array1).contains(a)) {
System.out.println("马超在这里");
}
//将数组转成set集合
Set<String> set=new HashSet<String>(Arrays.asList(array2));
System.out.println("set:"+set);
//将数组转成list集合
List<String> list_1=new ArrayList<String>();
for (int i = 0; i < array2.length; i++) {
list_1.add(array2);
}
System.out.println("list_1:"+list_1);
String[] arrStrings2={"1","2","3"};
List<String > list2=Arrays.asList(arrStrings2);
System.out.println("list2:"+list2);
//Arrays.fill()填充数组
int[] arr3=new int;
Arrays.fill(arr3, 10);//将数组全部填充10
System.out.println("arr3:"+arr3);
for (int i = 0; i < arr3.length; i++) {
System.out.println("arr3:"+arr3);
}
//数组排序
int[] arr4 = {3, 7, 2, 1, 9};
Arrays.sort(arr4);
System.out.println("arr4:"+arr4);
for (int i = 0; i < arr4.length; i++) {
System.out.println("arr4:"+arr4);
}
int[] arr5 = {3, 7, 2, 1, 9,3,45,7,8,8,3,2,65,34,5};
Arrays.sort(arr5, 1, 4);//从第几个到第几个之间的进行排序
for (int i = 0; i < arr5.length; i++) {
System.out.println("arr5:"+arr5);
}
//复制数组
int[] arr6 = {3, 7, 2, 1};
int[] arr7=Arrays.copyOf(arr6, 10);//指定新数组的长度
int[] arr8=Arrays.copyOfRange(arr6, 1, 3); //只复制从索引到索引之间的元素（不包括索引的元素）
for (int i = 0; i < arr8.length; i++) {
System.out.println(arr8);
}
//比较两个数组
int[] arr9 = {1, 2, 3, 4,5,6,7,8,9,0};
boolean arr10=Arrays.equals(arr6, arr9);
System.out.println(arr10);
//去重复
//利用set的特性
int[] arr11 = {1, 2, 3, 4,5,6,7,8,9,0,3,2,4,5,6,7,4,32,2,1,1,4,6,3};
Set<Integer> set2=new HashSet<Integer>();
for (int i = 0; i < arr11.length; i++) {
set2.add(arr11);
}
System.out.println(set2);
int[] arr12 = new int;
int j=0;
for (Integer i:set2) {
arr12=i;
}
System.out.println(Arrays.toString(arr12));
}
}
很厉害,算法题目里都经常用到的 这也可以吗？正切反切反转排序？ 因为java在实际环境中经常是多线程的应用，arrayLis并t不是线程安全的，实际使用list往往用一些线程安全的list类。
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