字符串aba ccde232d ehdba cac 有多少个不同字母，并且每个不同字母有多少个！

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class lzwCode {
	
	public static  void main(String [] args) {  
        String str = "ab accd12edehdb acac";  
        str = str.replaceAll("[^a-zA-Z]", "");
        int countNum = 0;  
        Map<Character, Integer> map = new HashMap<Character, Integer>();  
        for (int i=0; i<str.length(); i++) {  
            Character ch = new Character(str.charAt(i));  
            if (map.containsKey(ch)) {  
                map.put(ch, map.get(ch).intValue()+1);  
            } else {  
                map.put(ch, new Integer(1));  
            }  
        }  
        Iterator iter = map.entrySet().iterator();  
        while(iter.hasNext()) {  
            countNum++;  
            Map.Entry entry = (Map.Entry) iter.next();  
            Object key = entry.getKey();  
            Object val = entry.getValue();  
            System.out.println("字母"+key+"有"+val+"个");  
        }  
        System.out.println("一共有"+countNum+"字母");  
    }  
}

 

PHP

$str = "abaccdedehdbacac";
$arr = array();
for ($i=0; $i<strlen($str); $i++) {
	$key = $str[$i];
	if (array_key_exists($key, $arr)) {
		$arr[$key] = $arr[$key] + 1; 
	} else {
		$arr[$key] = 1;
	}
}
foreach($arr as $key=>$val) {
	echo "字母".$key."有".$val."个"."<br>";
}
echo "一共有".count($arr)."字母";

控制台结果：