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java enummap
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()方法用于检查此映射是否具有此枚举映射的给定键元素( 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()方法是一个非静态方法,只能由类对象访问,如果尝试使用类名访问该方法,则会收到错误消息。
containsKey() method does not throw an exception at the time of checking key mappings.
在检查键映射时, containsKey()方法不会引发异常。
Syntax:
句法:
public boolean containsKey(Object key_ele);
Parameter(s):
参数:
Object key_ele – represents the key element (key_ele) whose presence is to be checked.
对象key_ele –表示要检查其存在的关键元素(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.
此方法的返回类型为boolean ,当此枚举映射具有给定键元素(key_ele)的任何值时,它返回true,否则返回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 object EnumMap < Colors, String > em = new EnumMap < Colors, String > (Colors.class); // By using put() method is to // add the linked values in an EnumMap em.put(Colors.RED, "1"); em.put(Colors.BLUE, "2"); em.put(Colors.PINK, "3"); em.put(Colors.YELLOW, "4"); // Display EnumMap System.out.println("EnumMap :" + em); // By using containsKey() method isto // check whether this EnumMap contains // any value for the given key element // in an EnumMap boolean status = em.containsKey(Colors.PINK); // Display status of EnumMap System.out.println("em.containsKey(Colors.PINK): " + status); }}
Output
输出量
EnumMap :{RED=1, BLUE=2, PINK=3, YELLOW=4}em.containsKey(Colors.PINK): true
翻译自:
java enummap
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