1.声明数组
String [] arr;
int arr1[];
String[] array=new String[5];
int score[]=new int[3];
2.初始化数组
int arr2[]=new int[]{1,2,3,4,5};
String[] array1={“1”,”2”,”3”,”4”};
String[] array2=new String[]{“1”,”2”,”3”,”4”,”5”};
int score[]=new int[3];
3.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);
4.Array中创建ArrayList
ArrayList arrayList=new ArrayList(Arrays.asList(array1));
System.out.println(arrayList);
5.数组中是否包含某一个值
String a=”1”;
String[] array1={“1”,”2”,”3”,”4”,”5”};
if (Arrays.asList(array1).contains(a)) {
System.out.println(“find it”);
}
6.将数组转成set集合
String[] array2=new String[]{“1”,”2”,”3”,”4”,”5”};
Set set=new HashSet(Arrays.asList(array2));
System.out.println(set);
7.将数组转成list集合
String[] arrStrings2={“1”,”2”,”3”};
List list2=java.util.Arrays.asList(arrStrings2);
System.out.println(list2);
8.Arrays.fill()填充数组
int[] arr3=new int[5];
Arrays.fill(arr3, 10); //将数组全部填充10
//遍历输出
for (int i = 0; i < arr3.length; i++) {
System.out.println(arr3[i]);
}
9.数组排序
int[] arr4 = {3, 7, 2, 1, 9};
Arrays.sort(arr4); //.sort(int[] a) 放入数组名字
for (int i = 0; i < arr4.length; i++) {
System.out.println(arr4[i]);
}
10.复制数组
//方法 1.
int[] arr6 = {3, 7, 2, 1};
int[] arr7=Arrays.copyOf(arr6, 10); //指定新数组的长度
//方法 2.
int[] arr8=Arrays.copyOfRange(arr6, 1, 3); //只复制从索引[1]到索引[3]之间的元素（不包括索引[3]的元素）
for (int i = 0; i < arr8.length; i++) {
System.out.println(arr8[i]);
}
11.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);
12.最大值和最小值
int[] arr11 = {10, 2, 3, 4,5,6,7,8,9,0,3,2,4,5,6,7,4,32,2,1,1,4,6,3};
//计算最大值
int max = arr11[0];
for (int i = 1; i < arr11.length; i++) {
if (arr11[i] > max) {
max = arr11[i];
}
}
System.out.println(“Max is ” + max);
//计算最小值
int min = arr11[0];
for (int i = 0; i < arr11.length; i++) {
if (arr11[i] < min) {
min = arr11[i];
}
}
System.out.println(“Min is ” + min);