Java中的 Arrays.deepToString() 示例
Java.util.Arrays.deepToString(Object[]) 方法是一个Java.util.Arrays 类方法。
返回指定数组的“深层内容”的字符串表示形式。如果数组包含其他数组作为元素，则字符串表示包含它们的内容等等。此方法旨在将多维数组转换为字符串。简单的 toString() 方法适用于简单数组，但不适用于多维数组。此方法旨在将多维数组转换为字符串。
句法：
public static String deepToString(Object[] arr)
arr - An array whose string representation is needed
This function returns string representation of arr[].
It returns "null" if the specified array is null.例子：
Let us suppose that we are making a 2-D array of
3 rows and 3 column.
2 3 4
5 6 7
2 4 9
If use deepToString() method to print the 2-D array,
we will get string representation as :-
[[2,3,4], [5,6,7], [2,4,9]]
打印多维数组
// A Java program to print 2D array using deepToString()
import java.util.Arrays;
public class GfG
{
public static void main(String[] args)
{
// Create a 2D array
int[][] mat = new int[2][2];
mat[0][0] = 99;
mat[0][1] = 151;
mat[1][0] = 30;
mat[1][1] = 5;
// print 2D integer array using deepToString()
System.out.println(Arrays.deepToString(mat));
}
}
输出：
[[99, 151], [30, 5]] toString() 与 deepToString()
toString() 适用于一维数组，但不适用于多维数组。
// Java program to demonstrate that toString works if we
// want to print single dimensional array, but doesn't work
// for multidimensional array.
import java.util.Arrays;
public class Deeptostring
{
public static void main(String[] args)
{
// Trying to print array of strings using toString
String[] strs = new String[] {"practice.geeksforgeeks.org",
"quiz.geeksforgeeks.org"
};
System.out.println(Arrays.toString(strs));
// Trying to print multidimensional array using
// toString
int[][] mat = new int[2][2];
mat[0][0] = 99;
mat[0][1] = 151;
mat[1][0] = 30;
mat[1][1] = 50;
System.out.println(Arrays.toString(mat));
}
}
输出：
[practice.geeksforgeeks.org, quiz.geeksforgeeks.org]
[[I@15db9742, [I@6d06d69c]
注意：我们可以使用循环来使用 deepToString() 打印多维数组的内容。
deepToString() 适用于单维和多维，但不适用于单维基元数组
// Java program to demonstrate that deepToString(strs))
// works for single dimensional arrays also, but doesn't
// work single dimensional array of primitive types.
import java.util.Arrays;
public class Deeptostring
{
public static void main(String[] args)
{
String[] strs = new String[] {"practice.geeksforgeeks.org",
"quiz.geeksforgeeks.org"
};
System.out.println(Arrays.deepToString(strs));
Integer [] arr1 = {10, 20, 30, 40};
System.out.println(Arrays.deepToString(arr1));
/* Uncommenting below code would cause error as
deepToString() doesn't work for primitive types
int [] arr2 = {10, 20, 30, 40};
System.out.println(Arrays.deepToString(arr2)); */
}
}
输出：
[practice.geeksforgeeks.org, quiz.geeksforgeeks.org]
[10, 20, 30, 40]
参考：