Question

I have 2 arrays of data in Java. Based on the order of first array I have to sort the next array.
E.g –

String[] Array1 = {"EUROPE","MIDDLEEAST","OTHERs","AUSTRALIA"};
String[] Array2 = {"MIDDLEEAST","EUROPE","AUSTRALIA","OTHERs","ASIA","EUROPE"};

My output should look like:

{"EUROPE","EUROPE","MIDDLEEAST","OTHERs","AUSTRALIA","ASIA"}

What is the best way to do it?

Answer 1

To sort you need to define a sorting order so given element A and B, you can determine easily if A should go before or after B in the sorted list.

This concept is formalized with the concept of a Comparator in Java.

In this case the sorting order is defined by the order of the elements in a list. The simplest approach is given A and B to find each of them in the original list, note the index found, and compare the indexes to find out which one goes first.

Depending on the size of your data this might be too slow. You can then create a HashMap<String,Long> which holds the index of a given string in Array1. Here it would hold “DEF”->0, “ABC”->1, “XYZ”->2.