public class test { public static void main(String[] args) { // TODO Auto-generated method stub int[] a = {11,1,5,3,32,23}; Arrays.sort(a); for(int i : a){ System.out.println(i); } String str = Arrays.toString(a); System.out.printf("%s",str); int[] b = Arrays.copyOfRange(a, 3,4); for(int i : b){ System.out.printf("%d", i); } int index = Arrays.binarySearch(a, 3,4,32); System.out.printf("%s", index); int[] c = new int[5]; Arrays.fill(c,4); System.out.println(Arrays.toString(c)); //---java.lang.System int[] from = {1,2,53,4,25,16,27,18,9}; int[] to = {1,22,53,4,25,16,2,8,9}; System.arraycopy(from, 0, to, 1, 1); System.out.println(Arrays.toString(to)); //-- float[][] f = {{1,2,4},{3,1,2},{2,7,5}}; System.out.println(Arrays.deepToString(f)); for(float[] row : f ) for(float col : row) System.out.println(col); //---不规则数组 int[][] oods = new int[5][]; for(int i=0;i<5;i++){ oods[i] = new int[i+1]; } for(int[] row : oods){ for(int col : row){ System.out.print(col+"\t"); } System.out.println(); } }