求数组里相同数据个数

例如：数组里有元素，{"aa","bb","cc","aa","cc","aa"}，计算出个元素出现的次数。

结果应为：aa出现3次，bb出现1次，cc出现2次。

 

import java.util.ArrayList;import java.util.Arrays;import java.util.HashMap;import java.util.List;public class Test { /** * code:JAVA */ public static void main(String[] args) { // TODO Auto-generated method stub HashMap<String, Integer> map = new HashMap<String, Integer>(); String[] str = {"aa","bb","cc","aa","cc","aa"}; List l; l = Arrays.asList(str); for(int i = 0;i<l.size();i++){ if(map.containsKey(l.get(i))){ int num = map.get(l.get(i)); num++; map.put((String) l.get(i), num); }else{ map.put((String) l.get(i), 1); } } System.out.println(map); }}

 

 

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