java学习笔记27

java数组

arrays类讲解

打印数组元素

package array;
​
import java.util.Arrays;
​
public class Demo06 {
    public static void main(String[] args) {
        int[] a = {1,2,3,4,9090,31231,543,21,8,23};
        System.out.println(a);//[I@5fd0d5ae
        //打印数组元素Arrays.toString
        System.out.println(Arrays.toString(a));
        
    }
}

排序

package array;
​
import java.util.Arrays;
​
public class Demo06 {
    public static void main(String[] args) {
        int[] a = {1,2,3,4,9090,31231,543,21,8,23};
        Arrays.sort(a);//数组进行排序:升序
        System.out.println(Arrays.toString(a));
​
    }
}
[1, 2, 3, 4, 8, 21, 23, 543, 9090, 31231]

填充

package array;
​
import java.util.Arrays;
​
public class Demo06 {
    public static void main(String[] args) {
        int[] a = {1,2,3,4,9090,31231,543,21,8,23};
        Arrays.fill(a,0);
        System.out.println(Arrays.toString(a));
​
    }
}
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
​

package array;
​
import java.util.Arrays;
​
public class Demo06 {
    public static void main(String[] args) {
        Arrays.fill(a,2,4,0);
        System.out.println(Arrays.toString(a));
​
    }
}
[1, 2, 0, 0, 8, 21, 23, 543, 9090, 31231]