Sort specific parts in String-CodePudding

Alright so, I have a String which contains: 1 456 2 100 3 600 1 400

The 1 is the Id of a person which got a score of 456 and 400. 2 is the Id of a person which got a score of 100 etc.

I need the String to sort by values and not by id's. It should look like this: 2 100 1 400 1 456 3 600

I already tried putting it into a hashmap and sorting it, but since a hashmap doesn't take identical keys, this is not an option.

CodePudding user response：

Here is the full snippet, but as WJS commented, create a class:

public class Person {
    private String id;
    private int score;
    ...
}

Then add these to a List:

...
String[] parts = s.split(" ");
    
List<Person> people = new ArrayList<>();
for (int i = 0; i < parts.length; i  = 2) {
    String id = parts[i];
    int score = Integer.parseInt(parts[i 1]);
    people.add(new Person(id, score));
}

Then you sort the list by passing a comparator which compares scores and if you need it back in a String, join the list with spaces:

people.sort((p1, p2) -> Integer.compare(p1.score, p2.score));    
String result = people.stream().map(Person::toString).collect(Collectors.joining(","));

CodePudding user response：

Ok, here is how I did it. I used a record instead of a class as it creates the getters implicitly. No setters since a record is immutable.

record and data string

record Data (int id, int score) {
  @Override
  public String toString() {
      return"id=%d, score=%d".formatted(id, score);
  }
}
String data = "1 456 2 100 3 600 1 400";

create the list to hold the data
split on one or more white space characters
then for each (id, score) pair, create an instance of Data (I converted both to ints)
add the instance to the list
and sort the list

List<Data> list = new ArrayList<>();
String[] items = data.split("\\s ");
for(int i = 0; i < items.length; i =2) {
    list.add(new Data(Integer.parseInt(items[i]), Integer.parseInt(items[i 1])));
}
list.sort(Comparator.comparingInt(Data::value));
for (Data d : list) {
    System.out.println(d);
}

prints

id=2, score=100
id=1, score=400
id=1, score=456
id=3, score=600