java enummap

EnumMap類containsKey()方法 (EnumMap Class containsKey() method)

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

  containsKey()方法在java.util包中可用。

• containsKey() method is used to check whether this map has values for the given key element (key_ele) of this enum map.

  containsKey()方法用于檢查此映射是否具有此枚舉映射的給定鍵元素( key_ele )的值。

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

  containsKey()方法是一個(gè)非靜態(tài)方法，只能由類對象訪問，如果嘗試使用類名訪問該方法，則會收到錯誤消息。

• containsKey() method does not throw an exception at the time of checking key mappings.

  在檢查鍵映射時(shí)， containsKey()方法不會引發(fā)異常。

Syntax:

句法：

public boolean containsKey(Object key_ele);

Parameter(s):

參數(shù)：

• Object key_ele – represents the key element (key_ele) whose presence is to be checked.

  對象key_ele –表示要檢查其存在的關(guān)鍵元素(key_ele)。

Return value:

返回值：

The return type of this method is boolean, it returns true when this enum map have any value for the given key element (key_ele) otherwise it returns false.

此方法的返回類型為boolean ，當(dāng)此枚舉映射具有給定鍵元素(key_ele)的任何值時(shí)，它返回true，否則返回false。

Example:

例：

// Java program to demonstrate the example // of boolean containsKey(Object key_ele) method of EnumMapimport java.util.*;public class ContainsKeyOfEnumMap {public enum Colors {RED,BLUE,PINK,YELLOW};public static void main(String[] args) {// We are creating EnumMap objectEnumMap < Colors, String > em =new EnumMap < Colors, String > (Colors.class);// By using put() method is to// add the linked values in an EnumMapem.put(Colors.RED, "1");em.put(Colors.BLUE, "2");em.put(Colors.PINK, "3");em.put(Colors.YELLOW, "4");// Display EnumMapSystem.out.println("EnumMap :" + em);// By using containsKey() method isto// check whether this EnumMap contains// any value for the given key element// in an EnumMapboolean status = em.containsKey(Colors.PINK);// Display status of EnumMapSystem.out.println("em.containsKey(Colors.PINK): " + status);} }

Output

輸出量

EnumMap :{RED=1, BLUE=2, PINK=3, YELLOW=4} em.containsKey(Colors.PINK): true

翻譯自: https://www.includehelp.com/java/enummap-containskey-method-with-example.aspx

java enummap

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