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字典排序
-
- List<String> list=new ArrayList();
- //add list member
- Arrays.sort(list);
-
- List<Map<String,Integer>> list=new ArrayList();
- //add list member
- Collections.sort(list, new Comparator<Map.Entry<String, Integer>>() {
- @Override
- public int compare(Map.Entry<String, Integer> o1, Map.Entry<String, Integer> o2{
- return o2.getValue()-o1.getValue();
- }
- });
进制转换
Integer.parseInt(hexString, 16)//16进制转10进制
Integer.toBinaryString(num);//十进制转二进制
int decimal = Integer.parseInt(binaryString, 2);//二进制转10进制
>> 有符号右移
>>>无符号右移
bit处理
Integer.bitCount(n);//二进制中1的个数
字典排序示例:
- package huaweiod;
-
- import java.util.*;
-
- public class Test{
- public static void main(String[] args) throws Exception{
- Map<String,Map<String,Integer>> map=new HashMap();
- Map<String,Integer> map1=new HashMap();
- map1.put("004",160);
- map1.put("003",150);
- map1.put("002",150);
- map1.put("001",160);
- map1.put("005",150);
- map.put("02",map1);
-
- Map<String,Integer> map2=new HashMap();
- map2.put("003",130);
- map2.put("004",140);
- map.put("01",map2);
-
- Set<String> classNum=map.keySet();
- Object[] array=classNum.toArray();
- Arrays.sort(classNum.toArray());
- for(Object o:array){
- System.out.println("class:"+o);
- HashMap<String,Integer> tempMap=(HashMap)map.get(o);
- List<Map.Entry<String,Integer>> list=new ArrayList(tempMap.entrySet());
- Collections.sort(list, new Comparator<Map.Entry<String, Integer>>() {
- @Override
- public int compare(Map.Entry<String, Integer> o1, Map.Entry<String, Integer> o2) {
- return o2.getValue()-o1.getValue();
- }
- });
- for(Map.Entry<String,Integer> entry:list){
- System.out.println(entry.getKey()+":"+entry.getValue());
- }
- }
- }
- }
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