Java 程式以檢索 HashMap 中所有的鍵值對集
要從 HashMap 檢索鍵集,請使用 keyset() 方法。但是,對於值集,請使用 values() 方法。
建立一個 HashMap −
HashMap hm = new HashMap(); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600)); hm.put("Backpack", new Integer(1200));
現在,檢索鍵 −
Set keys = hm.keySet(); Iterator i = keys.iterator(); while (i.hasNext()) { System.out.println(i.next()); }
檢索值 −
Collection getValues = hm.values(); i = getValues.iterator(); while (i.hasNext()) { System.out.println(i.next()); }
以下是一個示例,用於獲取 HashMap 中所有鍵值對的集合 −
示例
import java.util.*; public class Demo { public static void main(String args[]) { // Create hash map HashMap hm = new HashMap(); hm.put("Wallet", new Integer(700)); hm.put("Belt", new Integer(600)); hm.put("Backpack", new Integer(1200)); System.out.println("Map = "+hm); System.out.println("
Keys..."); Set keys = hm.keySet(); Iterator i = keys.iterator(); while (i.hasNext()) { System.out.println(i.next()); } System.out.println("
Values..."); Collection getValues = hm.values(); i = getValues.iterator(); while (i.hasNext()) { System.out.println(i.next()); } } }
輸出
Map = {Backpack=1200, Belt=600, Wallet=700} Keys... Backpack Belt Wallet Values... 1200 600 700
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