ArrayList類isEmpty()方法 (ArrayList Class isEmpty() method)

• isEmpty() method is available in java.util package.

  isEmpty()方法在java.util包中可用。

• isEmpty() method is used to check whether this Arraylist is "empty" or "not empty".

  isEmpty()方法用于檢查此Arraylist是“空”還是“非空”。

• isEmpty() method is a non-static method so it is accessible with the class object and if we try to access the method with the class name then we will get an error.

  isEmpty()方法是一個非靜態方法，因此可以通過類對象進行訪問，如果嘗試使用類名訪問該方法，則會收到錯誤消息。

• isEmpty() method does not throw an exception at the time of checking the status of an empty Arraylist.

  在檢查空Arraylist的狀態時， isEmpty()方法不會引發異常。

Syntax:

句法：

public boolean isEmpty();

Parameter(s):

參數：

• It does not accept any parameter.

  它不接受任何參數。

Return value:

返回值：

The return type of this method is boolean, it returns true when this Arraylist is "empty" otherwise it returns false when this Arraylist is "non-empty".

此方法的返回類型為boolean ，當此Arraylist為“空”時返回true；否則，當此Arraylist為“非空”時返回false。

Example:

例：

// Java program to demonstrate the example // of boolean isEmpty() method of ArrayListimport java.util.*;public class EmpytArrayList {public static void main(String[] args) {// Create an ArrayList with initial // capacity of storing elementsArrayList arr_l = new ArrayList(10);// By using add() method is to add // elements in this ArrayListarr_l.add("C");arr_l.add("C++");arr_l.add("JAVA");arr_l.add("DOTNET");arr_l.add("PHP");// Display ArrayListSystem.out.println("ArrayList Elements :" + arr_l);// By using isEmpty() method is to check// the empty ArrayListboolean status = arr_l.isEmpty();// Display status of the given ArrayListSystem.out.println("arr_l.isEmpty() : " + status);} }

Output

輸出量

ArrayList Elements :[C, C++, JAVA, DOTNET, PHP] arr_l.isEmpty() : false

翻譯自: https://www.includehelp.com/java/arraylist-isempty-method-with-example.aspx

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