How to sort Array in java?

Question

Hello i have some simple code like this

  String[] myString1= {"Hidayat", "20"};
  outerArr.add(myString1);

  String[] myString2= {"Ryan", "10"};
  outerArr.add(myString2);

  String[] myString2= {"irwan", "5"};
  outerArr.add(myString2);

anyone know how to sort array outerArr with ascending by number?

What type of list you are using for outerArr? – EtherPaul Jan 12 '17 at 10:48 — EtherPaul, Jan 12 '17 at 10:48
http://alvinalexander.com/java/how-sort-java-string-array – IntelliJ Amiya Jan 12 '17 at 11:00 — IntelliJ Amiya, Jan 12 '17 at 11:00

Sergei Bubenshchikov · Accepted Answer · 2017-01-12T10:54:23.797

1

You can use Comparator interface for custom sorting:

Collections.sort(outerArr, new Comparator<String[]>() {
    public int compare(String[] o1, String[] o2)
    {
        // for example you can compare integers
        return Integer.parseInt(o2[1]) - Integer.parseInt(o1[1]);
    }
});

edited Jan 12 '17 at 10:54

answered Jan 12 '17 at 10:48

Sergei Bubenshchikov

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thx before, but how if an array is dynamic with loop – user7328700 Jan 12 '17 at 10:58
Your array changed at sorting time? – Sergei Bubenshchikov Jan 12 '17 at 11:00
1

This is off topic on this post, but this will depends on your "dynamic array". – AxelH Jan 12 '17 at 11:00

score 0 · Answer 2 · answered Jan 12 '17 at 10:51

0

For that case i prefer TreeMap.The TreeMap class implements the Map interface by using a tree. A TreeMap provides an efficient means of storing key/value pairs in sorted order, and allows rapid retrieval.

TreeMap<String, String> map = new TreeMap<>();
map.put("20", "Hidayat");
map.put("10", "Ryan");
map.put("5", "irwan");

For retrieving the values

map.get("10"); // output = Ryan

answered Jan 12 '17 at 10:51

Deepak Goyal

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You should add that this has some cost on each insertion, suppression of course so this depends on the usage. For a pretty static map, this is not a problem, for a list that will be update a lot but only need to be sorted (printed or used) once in a while, I would stay with a list – AxelH Jan 12 '17 at 10:52

Abdennacer Lachiheb · Answer 3 · 2017-01-12T11:09:46.350

0

Another way to do this if you are using Java 8 is using Lambda, first create a class contain 2 member fields for the string and the number with getter for each member and then called this way :

outerArr.sort((Person o1, Person o2)->o1.getAge()-o2.getAge());

If you don't want to create a new class you can call :

outerArr.sort((String[] o1, String[] o2)->Integer.parseInt(o1[1])-Integer.parseInt(o2[1]));

edited Jan 12 '17 at 11:09

answered Jan 12 '17 at 11:01

Abdennacer Lachiheb

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How to sort Array in java?

3 Answers3