java如何统计字符串中每个字符出现的次数

发布网友发布时间：2022-05-02 01:40

共3个回答

懂视网时间：2022-05-02 06:01

java.util.Iterator; import java.util.Map; import java.util.Set; import java.util.TreeMap; /* * 统计abacbacdadbc中的每个字母出现的次数，输出格式是：a(4)b(3)c(3)d(2) * * 选中TreeMap的原因是:key不重复且按顺序排序取出 * * 思路： * 1.将字符串abacbacdadbc转换成字符数组 * 2.分别取字符，与TreeMap中的key进行比较 * 2.1 如果TreeMap中存在对应的字符，则取出并自增，再存入TreeMap * 2.2 如果TreeMap中不存在对应的字符，则直接存入该字符，value=1 */ public class A3B1C2_TreeMapTest { public static void main(String[] args) { TreeMap<String, Integer> tm=new TreeMap<>(); String string="abacbacdadbc"; char[] ch=string.toCharArray(); for(char r :ch){ //tm.put(String.valueOf(r), 1); //System.out.println(r); if(compareKey(r, tm)) { int i=tm.get(String.valueOf(r)); i++; tm.put(String.valueOf(r), i); }else { tm.put(String.valueOf(r), 1); } } System.out.println(tm); Set<Map.Entry<String, Integer>> entrySet=tm.entrySet(); Iterator<Map.Entry<String, Integer>> iterator=entrySet.iterator(); while(iterator.hasNext()){ Map.Entry<String, Integer> me=iterator.next(); String key=me.getKey(); int value=me.getValue(); System.out.print(key+"("+value+")"); } } public static boolean compareKey(char c,TreeMap<String, Integer> treeMap){ if (treeMap.containsKey(String.valueOf(c))) { return true; } return false; } }

java统计abacbacdadbc中的每个字母出现的次数，输出格式是：a(4)b(3)c(3)d(2)

标签：dad boolean 输出 ati sys color blog ++ 统计

热心网友时间：2022-05-02 03:09

正确答案：

import java.util.Iterator;
import java.util.Map;
import java.util.TreeMap;

public class Test {

@SuppressWarnings("unchecked")
public static void main(String[] args) {

String str = null;
try {
str = args[0];
} catch (ArrayIndexOutOfBoundsException e) {
System.out.println("请输入参数!");
System.exit(0);
}
Map tree = new TreeMap();

for (int i = 0; i < str.length(); i++) {
char ch = str.charAt(i);
if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z')) {
if (!tree.containsKey(ch)) {
tree.put(ch, new Integer(1));
} else {
Integer in = (Integer) tree.get(ch) + 1;
tree.put(ch, in);
}
}
}
Iterator tit = tree.keySet().iterator();
while (tit.hasNext()) {
Object temp = tit.next();
System.out.print(temp.toString() + "(" + tree.get(temp) + ")");
}
}
}

热心网友时间：2022-05-02 04:27

package org.zj.sample;

public class Test {
char array_char[];

public int getInstances(String all, String choice) {
int total=0;
array_char=all.toCharArray();
for(int i=0;i<array_char.length;i++){
if (array_char[i]==(choice.charAt(0))){
total++;
}
}
return total;
}

public static void main(String[] args){
String appearance=new String("ADBCA ADCBACDBC BDA");
Test t=new Test();
System.out.println("A: " + t.getInstances(appearance, "A"));
System.out.println("B: " + t.getInstances(appearance, "B"));
System.out.println("C: " + t.getInstances(appearance, "C"));
System.out.println("D: " + t.getInstances(appearance, "D"));
}
}