如何将一维数组分解成行

Question

我想把一维数组分解成行。阵列尺寸50。我需要将数组输出到控制台，每行10个元素。(lang Java 1.8(谢谢！

public void print() {
for (int i = 0; i < arr.length; i++) {
if (i<=9) {
System.out.print(arr[i] + " ");
}else {
System.out.print("r");
}
}
}

样本输出

0 1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 
etc....

Answer 1

您可以从的两个不同角度看到它

1. 每10个数字，打印一行新行：当索引以9结束时，您将达到10个元素，因此您将打印一行新的println()

   public void print() {
   for (int i = 0; i < arr.length; i++) {
   System.out.print(arr[i] + " ");
   if (i % 10 == 9) {
   System.out.println();
   }
   }
   }
   

2. 打印足够数量的行，每个行上：打印10个元素

   public void print() {
   for (int i = 0; i < arr.length / 10; i++) {
   for (int j = 0; j < 10; j++) {
   System.out.print(arr[i * 10 + j] + " ");
   }
   System.out.println();
   }
   }
   

Answer 2

每行任意数量元素的代码：

public void print(int elementsPerLine) {
for (int i = 0; i < arr.length; i++) {
System.out.print(arr[i]);
if (i % elementsPerLine == 0 && i > 0) {
System.out.println();
} else {
System.out.print(" ");
}
}
}

Answer 3

使用以下代码，

public static void printResult(int[][] result)
{
for(int i=0; i<5; i++)
{
for(int j=0; j<10; j++)
{
System.out.print(result[i][j] + ", ");
}
System.out.println();
}
}
public static int[][] modifyArray( int[] singleArray )
{
int columns = 10;
int rows = singleArray.length/10;
int[][] result = new int[rows][columns];
for(int i=0; i<rows; i++)
{
for(int j=0; j<columns; j++)
{
result[i][j] = singleArray[columns*i + j];
}
}
return result;
}

public static void main(String[] args)
{
int[] singleArray = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50};
int[][] result = modifyArray( singleArray);
printResult( result );
}

Answer 4

必须使用模运算符https://en.wikipedia.org/wiki/Modulo_operation

public void print() {
for (int i = 0; i < arr.length; i++) {
if (i%10 == 0) {
System.out.print("r");
}else {
System.out.print(arr[i] + " ");
}
}
}

Answer 5

也许你可以写一些类似的东西

if (i % 10 == 0)
System.out.print("r");
}
System.out.print(arr[i] + " ");

Answer 6

每次将10个项目的切片放入一个新数组，并打印该数组：

int count = 10;
int iterations = (arr.length / count) +  ((arr.length % count) > 0 ? 1 : 0);
for (int i = 1; i <= iterations; i++) {
int[] slice = new int[count];
System.arraycopy(arr, (i - 1) * count, slice, 0, i == iterations ? (array.length % count) : count);
System.out.println(Arrays.toString(slice));
}

上面的代码适用于count的任何值。

Answer 7

看看下面的代码：

public class PrintEach10thElements {
/**
* @param args the command line arguments
*/
static List<Integer> arrays = new ArrayList<>();
public static void main(String[] args) {
//create 50 elements in an array
for (int i = 0; i <= 49; i++) {
arrays.add(i);
}
for (int g = 0; g < arrays.size(); g++) {
if ( arrays.get(g) % 10 != 0) {
System.out.print(arrays.get(g) + " ");
} else {
System.out.println();
System.out.print(arrays.get(g) + " ");
}
}
}
}

Answer 8

如果你不介意使用Guava库，你也可以做这个

List<Integer> myList = Arrays.asList(myArray);
System.out.println(Lists.partition(myList, 10).stream()
.map(subList -> subList.stream()
.map( Object::toString )
.collect(Collectors.joining(" ")))
.collect(Collectors.joining("n")));