在Java中，數(shù)組長(zhǎng)度是數(shù)組可以容納的元素?cái)?shù)。沒(méi)有預(yù)定義的方法來(lái)獲取數(shù)組的長(zhǎng)度。我們可以使用數(shù)組屬性長(zhǎng)度在Java中找到數(shù)組長(zhǎng)度。我們將此屬性與數(shù)組名一起使用。在本節(jié)中，我們將學(xué)習(xí)如何在Java中查找數(shù)組的長(zhǎng)度或大小。

數(shù)組長(zhǎng)度屬性

Java提供了一個(gè)屬性長(zhǎng)度，用于確定數(shù)組的長(zhǎng)度。每個(gè)數(shù)組都有一個(gè)內(nèi)置長(zhǎng)度屬性，其值為數(shù)組的大小。Size表示數(shù)組可以包含的元素總數(shù)?？梢允褂命c(diǎn)(.)運(yùn)算符后跟數(shù)組名稱(chēng)來(lái)調(diào)用length屬性。我們可以找到int[]、double[]、String[]等的長(zhǎng)度。例如：

int[] arr=new int[5];  
int arrayLength=arr.length  

在上面的代碼片段中，arr是一個(gè)int類(lèi)型的數(shù)組，可以容納5個(gè)元素。arrayLength是存儲(chǔ)數(shù)組長(zhǎng)度的變量。為了找到數(shù)組的長(zhǎng)度，我們分別使用了數(shù)組名(arr)，后跟點(diǎn)運(yùn)算符和長(zhǎng)度屬性。它決定數(shù)組的大小。

請(qǐng)注意，長(zhǎng)度決定了數(shù)組可以包含的最大元素?cái)?shù)或數(shù)組的容量。它不計(jì)算插入數(shù)組的元素。也就是說(shuō)，length返回?cái)?shù)組的總大小。對(duì)于其元素在創(chuàng)建時(shí)初始化的數(shù)組，長(zhǎng)度和大小是相同的。

如果我們討論邏輯大小，數(shù)組的索引，那么只需intarrayLength=arr。長(zhǎng)度為-1，因?yàn)閿?shù)組索引從0開(kāi)始。因此，邏輯或數(shù)組索引總是小于實(shí)際大小1。

讓我們通過(guò)一個(gè)例子來(lái)找到數(shù)組的長(zhǎng)度。

例子1

public class ArrayLengthExample1  
{   
public static void main(String[] args)   
{   
//defining an array of type int named num  
//the square bracket contain the length of an array  
int[] num = new int[10];   
//length is an Array attribute that determines the array length   
int arrayLength=num.length;  
//prints array length  
System.out.println("The length of the array is: "+ arrayLength);   
}   
}  

輸出：

The length of the array is: 10

例子2

public class ArrayLengthExample2   
{   
public static void main(String[] args)   
{   
//initializing an array of type String named country   
String[] country = { "India", "Australia", "Japan", "USA", "UAE", "Canada", "Brazil"};  
//length is an Array attribute that determines the array length   
int arrayLength=country.length;   
//prints array length  
System.out.println("The size of the array is: " + arrayLength);   
}   
}  

輸出：

The size of the array is: 7

例子3

public class ArrayLengthExample3   
{  
private static void LengthOfArray(String[] array)   
{  
//checks array is empty or not      
if (array == null)   
{  
//if the array is empty prints the following statement  
System.out.println("The array is empty, can't be determined length.");  
}   
else   
{  
//length attribute of the Array class determines the length of an array  
int arrayLength = array.length;  
//prints the array length  
System.out.println("The length of the array is: "+arrayLength);  
}  
}  
public static void main(String[] args)   
{  
String[] fruits = { "Guava", "Banana", "Apple", "Papaya", "Melon", "Strawberry"};  
String[] alphabets = { "m", "p", "k", "l", "t" };  
String[] numbers = { "12", "25", "63", "84", "90", "11", "54"};  
//passing null value to the function  
LengthOfArray(null);  
//passing fruits array to the function  
LengthOfArray(fruits);  
//passing alphabets array to the function  
LengthOfArray(alphabets);  
//passing numbers array to the function  
LengthOfArray(numbers);  
}  
}  

輸出

The array is empty, can't be determined length.
The length of the array is: 6
The length of the array is: 5
The length of the array is: 7