声明数组:
int[] a String[] a = new String[]
初始化:
int[] a = new int[]{1,2,3,4} String[] a = {"a","b"} String[] a =new String[]{"a","b"}
长度:
a.length
int数组转成String数组:
String b = Arrays.toString(a)
数组转String:
String.copyValueOf(char[])
从Array中创建ArrayList:
ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(a))
数组中是否包含某一值:
Arrays.asList(array).contains(a)
数组转为Set集合:
Set<String> set = new HashSet<String>(Arrays.asList(a))
Arrays.fill()填充数组:
Arrays.fill(a,10):将数组a全部填充10
数组排序:
Arrays.sort(a)
Arrays.sort(a,from,to)
复制数组:
b = Arrays.copyOf(a,100):指定新数组长度
b = Arrays.copyOfRange(a,1,3):从索引1到索引3,不包括索引3
比较两个数组:
boolean c = Arrays.equals(a,b)
利用Set去重复:
Set<Integer> set = new HashSet<Integer>();
for(int i = 0; i < a.length; i++){
set.add(a[i]);
}
转为数组:
int[] arrayResult = (int[]) set.toArray(new int[set.size()]);
或者:
int[] b = new int[set.size()];
int j = 0;
for(Integer i : set){
b[j++] = i
}
打印数组:要用Arrays.toString(a),否则打印的是哈希地址
System.out.print(Arrays.toString(a))
连接两个数组:
System.arraycopy(O src, int srcstart, O dest, int deststart, int length)
声明内联数组:
method(new String[]{"a","b"}
ArrayList转为数组:
String[] result = arrayList.toArray(new String[arrayList.size()])