package com.qiku.day18;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class Zuo01 {
public static void main(String[] args) {
//1、产生10个1-100的随机数，并放到一个数组中，
//把数组中大于等于10的数字放到一个list集合中，并打印到控制台。
int[] arr = new int[10];
for (int i = 0; i < arr.length; i++) {
arr[i] = (int) (Math.random()*99+1);
}
System.out.println(Arrays.toString(arr));
List<Integer> list = new ArrayList<>();
for (int i = 0; i < arr.length; i++) {
if (arr[i] >= 10){
list.add(arr[i]);
}
}
System.out.println(list);
}
}
package com.qiku.day18;
import java.util.*;
public class Zuo02 {
public static void main(String[] args) {
//2、已知数组存放一批QQ号码，QQ号码最长为11位，最短为5位
//String[] strs ={"12345","67891","12347809933","98765432102","67891","12347809933"}。
// 将该数组里面的所有qq号都存放在LinkedList中，将list中重复元素删除，
// 将list中所有元素分别用迭代器和增强for循环打印出来。
String[] strs ={"12345","67891","12347809933","98765432102","67891","12347809933"};
Set<String> set = new HashSet<>();
for (int i = 0; i < strs.length; i++) {
set.add(strs[i]);
}
System.out.println(set);
List<String> list = new LinkedList<>();
Iterator<String> it = set.iterator();
while (it.hasNext()){
list.add(it.next());
}
System.out.println("迭代器："+list);
System.out.print("增强for循环:");
for (String str: list){
System.out.print(" "+str);
}
}
}
package com.qiku.day18;
public class Student implements Comparable<Student>{
private String name;
private int age;
private float score;
public Student(String name, int age, float score) {
this.name = name;
this.age = age;
this.score = score;
}
@Override
public int compareTo(Student o) {
if (this.score == o.score){
return this.age - o.age;
}
return o.score - this.score > 0 ? 1 : -1;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
", score=" + score +
'}';
}
public String getName() {return name;}
public void setName(String name) {this.name = name;}
public int getAge() {return age;}
public void setAge(int age) {this.age = age;}
public float getScore() {return score;}
public void setScore(float score) {this.score = score;}
}
package com.qiku.day18;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
public class Zuo03 {
public static void main(String[] args) {
//3、用Comparable接口对下列四位同学的成绩做降序排序，
// 如果成绩一样，那在成绩排序的基础上按照年龄由小到大排序。
Student stu1 = new Student("liusan", 20, 90);
Student stu2 = new Student("lisi",22,90);
Student stu3 = new Student("wangwu",20,99);
Student stu4 = new Student("sunliu",22,100);
List<Student> list = new ArrayList<>();
list.add(stu1);
list.add(stu2);
list.add(stu3);
list.add(stu4);
System.out.println(list);
Collections.sort(list);
System.out.println(list);
}
}
package com.qiku.day18;
import java.util.*;
public class Zuo04 {
public static void main(String[] args) {
Map<Integer, String> map = new HashMap<Integer, String>();
map.put(1, "张三丰");
map.put(2, "周芷若");
map.put(3, "汪峰");
map.put(4, "灭绝师太");
System.out.println(map);
map.put(5,"李晓红");
map.remove(1);//根据key删除元素
map.put(2,"周林");
System.out.println(map);
System.out.println("============");
//1
Set<Integer> keys = map.keySet();
Iterator<Integer> itKey = keys.iterator();
while (itKey.hasNext()){
Integer key = itKey.next();
String value = map.get(key);
System.out.println(key+":"+value);
}
//2
Collection<String> values = map.values();
Iterator<String> valueIt = values.iterator();
while (valueIt.hasNext()){
String value = valueIt.next();
System.out.println(value);
}
//3 通过遍历所有的enter 遍历map
//
Set < Map.Entry < Integer,String > > entries = map.entrySet();
Iterator<Map.Entry<Integer,String>>entryIt = entries.iterator();
while (entryIt.hasNext()){
Map.Entry<Integer,String> entry = entryIt.next();
Integer key = entry.getKey();
String value = entry.getValue();
System.out.println(key+"："+value);
}
}
}
package com.qiku.day18;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
public class Zuo05 {
public static void main(String[] args) {
/**
* 5、已知有十六支男子足球队参加2020 奥运会。写一个程序，把这16 支球队随机分为4 个组。
* 采用List集合和随机数
* 2020 奥运会男足参赛国家：
* 科特迪瓦，阿根廷，澳大利亚，塞尔维亚，荷兰，尼日利亚、日本，美国，中国，
* 新西 兰，巴西，比利时，韩国，喀麦隆，洪都拉斯，意大利
*/
String[] strs = {" 科特迪瓦","阿根廷","澳大利亚","塞尔维亚","荷兰","尼日利亚","日本","美国" ,
"中国","新西兰","巴西","比利时","韩国","喀麦隆","洪都拉斯","意大利"};
List<String> list1 = new ArrayList<>();
List<String> list2 = new ArrayList<>();
List<String> list3 = new ArrayList<>();
List<String> list4 = new ArrayList<>();
List<String> list = new ArrayList<>();
for (int i = 0; i < strs.length; i++) {
list.add(strs[i]);
}
System.out.println(list);
for (int i = 0;i < strs.length;i++){
int index = (int) (Math.random()*list.size());
if(i<4){
list1.add(list.get(index));
list.remove(list.get(index));
} if(i>=4 && i<8){
list2.add(list.get(index));
list.remove(list.get(index));
} if(i>=8 && i<12){
list3.add(list.get(index));
list.remove(list.get(index));
} if(i>=12 && i<16){
list4.add(list.get(index));
list.remove(list.get(index));
}
}
System.out.println(list1);
System.out.println(list2);
System.out.println(list3);
System.out.println(list4);
}
}
