How to repeatedly add the same element to an array, I am new beginner in Java, could anyone help me solve this problem
For example,
When N = 1
int[] a1 = {1,2,3}
When N = 2
the result is
a1 = {1,2,3,1,2,3}
what's about 2-d array?
N is the number of rows
When N = 1
int[][] a1 = {{1,2,3},{4,5,6},{7,8,9}}
When N= 2
a2 = {{1,2,3},{4,5,6},{7,8,9}
{1,2,3},{4,5,6},{7,8,9}}
答案 0 :(得分:0)
根据您提供的示例,在我看来,您希望重复将相同的元素 s (复数)添加到您的数组中特定N次。
由于数组的大小是固定的,因此您无法声明
int[] a1 = {1,2,3};
然后尝试向其添加更多元素。这就是为什么我建议你使用ArrayList。下面是一个如何创建ArrayList并重复添加相同元素的示例。
// number of times you want to add elements (1, 2, 3)
int timesToRepeat = 2;
// your ArrayList instance
ArrayList<Integer> a1 = new ArrayList<Integer>();
// use add() to add the integer elements 1, 2, 3
a1.add(1);
a1.add(2);
a1.add(3);
// clone a1 so we have a non-changing copy of it when we get to our for loop
ArrayList<Integer> a1copy = (ArrayList<Integer>) a1.clone();
// here's where it will take the three elements (1, 2, 3) from a1copy
// it will repeatedly add them to a1 as many times as you specified
// you specify this number when setting the int variable timesToRepeat
for (int i = timesToRepeat; i > 1; --i) {
a1.addAll(a1copy);
}
// print your ArrayList
System.out.println(a1);
您还可以使用addAll()
创建一个二维数组列表并执行相同的操作,以多次添加元素模式。