附上代碼
package com.Gaga.assignment_3;
import java.util.HashMap;
public class Case6_Map_4 {
public static void main(String[] args) {
//創建字符串
final String s = "aaaaaabbbbbbbccccccdddddeeeeeffffffggggggggggggggggggggggggghh";
//創建字符數組,存放各個元素
char [] arr = s.toCharArray();
//創建HashMap集合
HashMap<Character, Integer> hm = new HashMap<>();
//通過增強for循環遍歷字符集合
for(char c : arr) {
/*通過Value值進行統計———— 使用ifelse判斷語句
* if(!hm.containsKey(c)) {
hm.put(c, 1);
}else {
hm.put(c, hm.get(c)+1);
}*/
//優化統計代碼
hm.put(c,!hm.containsKey(c)? 1 : hm.get(c)+1 );
}
//遍歷鍵的集合
for (Character c2 : hm.keySet()) {
System.out.println(c2+": "+hm.get(c2));
}
}
}
測試結果:
a: 6
b: 7
c: 6
d: 5
e: 5
f: 6
g: 25
h: 2