Java String Array

Question

i have two array

String a[]={"11","02","43","24","05","86","37","28","29","10"};
String b[]={"a","c","f","q","w","x","z","x","s","r"};

i want to sort array a[] in ascending order

and the result may like

String a[]={"02","05","10","11","24","28","29","37","43","86"};
String b[]={"c","w","r","a","q","x","s","z","f","x"};

how can i get result like above using java? any sorting method available in java?

Answer 1

The easiest way would be to link the 2 pieces of data together in some way instead of having them in separate arrays. Many people have suggested a Map which would work great. Depending on exactly what you are trying to do, I would also consider a new class with 2 variables that implement Comparable. Comparable defines the natural ordering of a class when it is in a Collection (in this instance an array) if Collections.sort is not given a different Comparator to use. It would look something like this:

    public class Data implements Comparable{ 
    private String stringOne;
    private String stringTwo;

    @Override
    public int compareTo(Object obj) {
        stringOne.compareTo((String)obj);
    }

Somewhere else call:

    Collections.sort(locationOfDataCollection);

You could then create one Collection of Data and access the other String with a getter method. This implementation also would make it simple in future (see Strategy Design) if in some instances the natural order needed to be overridden with a new Comparator (e.g. sort by stringTwo).

Answer 2

Since you have 2 related sets of data, I would either link these via a Pair<String,String> type object and then into a List<Pair>, or put them into a Map<String,String>.

Perhaps the first solution is more intuitive e.g.

public class Pair implements Comparable<Pair> {
   public String first;
   public String second;

   // equals/hashcode etc.
}

Once they're in a standard Java collection, numerous solutions exist for sorting these. e.g. in the above Pair I've implemented the Comparable<T> interface which the Collections sorting mechanisms will make use of.