一、将单词统计出来
package mypro01; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Set; //分拣存储--》分类归类 public class MapDemo01 { public static void main(String[] args) { //分割字符串 String[] arr="this is a cat and that is a nice is dang jing is ".split(" "); //分拣存储 Map<String,Integer> map=new HashMap<String,Integer>(); for(String key:arr) { if(!map.containsKey(key)) { map.put(key, 1); }else { map.put(key, map.get(key)+1); } } //查看每个单词出现的次数 Set<String> ketSet = map.keySet(); Iterator<String> it = ketSet.iterator(); while(it.hasNext()) { String key = it.next(); Integer value=map.get(key); System.out.println("key:"+key+"----->value:"+value); } } }
二、面向对象存储
package mypro01;
public class Student {
private String name;
private String id;
private double score;
public Student(String name, String id, double score) {
super();
this.name = name;
this.id = id;
this.score = score;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public double getScore() {
return score;
}
public void setScore(double score) {
this.score = score;
}
}
package mypro01;
import java.util.ArrayList;
import java.util.List;
public class ClassRoom {
private String no;
private List<Student> stuList;
private double total;
public ClassRoom(String no, List<Student> stuList, double total) {
super();
this.no = no;
this.stuList = stuList;
this.total = total;
}
public String getNo() {
return no;
}
public void setNo(String no) {
this.no = no;
}
public List<Student> getStuList() {
return stuList;
}
public void setStuList(List<Student> stuList) {
this.stuList = stuList;
}
public double getTotal() {
return total;
}
public void setTotal(double total) {
this.total = total;
}
public ClassRoom() {
stuList=new ArrayList<Student>();
}
public ClassRoom(String no) {
this();
this.no=no;
}
}
package mypro01;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class MapDemo02 {
public static void main(String[] args) {
//靠手
List<Student> stulist=exam();
Map<String,ClassRoom> map=count(stulist);
view(map);
}
//计算分数
public static void view(Map<String,ClassRoom> map) {
Set<String> keyset=map.keySet();
Iterator<String> itkey=keyset.iterator();
while(itkey.hasNext()) {
String no=itkey.next();
ClassRoom room=map.get(no);
double total=room.getTotal();
double avg=total/room.getStuList().size();
System.out.println(no+"--->"+total+"--->"+avg);
}
}
//分类
public static Map<String,ClassRoom> count(List<Student> list){
Map<String,ClassRoom> map=new HashMap<String,ClassRoom>();
for(Student stu:list) {
String no=stu.getId();
double score=stu.getScore();
ClassRoom room=map.get(no);
if(null==room) {
room =new ClassRoom(no);
map.put(no, room);
}
room.getStuList().add(stu);
room.setTotal(room.getTotal()+score);
}
return map;
}
//模拟考试成绩到其中
public static List<Student> exam(){
List<Student> list=new ArrayList<Student>();
list.add(new Student("张三","1",80));
list.add(new Student("李四","2",40));
list.add(new Student("王五","1",44));
list.add(new Student("马六","2",22));
list.add(new Student("马2","3",22));
return list;
}
}
结果:
1--->124.0--->62.0
2--->62.0--->31.0
3--->22.0--->22.0