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up vote 0 down vote favorite

I need to sort an array of strings like the following, by a substring of characters:

[0] = "gtrd3455";
[1] = "wsft885";
[2] = "ltzy96545";
[3] = "scry5558";
[4] = "lopa475";

I need to sort by the following "3455, 885, 96545, 5558, 475" I need to substring off the first 4 characters of the array, sort it and display back in an array like the output below.

The output should be an array like:

[0] = "ltzy96545";
[1] = "scry5558";
[2] = "gtrd3455";
[3] = "wsft885";
[4] = "lopa475";

Example of how I can do this in Java?

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2  
What have you tried so far? –  Rohit Jain Oct 24 '12 at 19:19

1 Answer 1

up vote 3 down vote accepted

You can use a Comparator, and use Array#sort method with it, to sort it according to your need: -

String[] yourArray = new String[3];
yourArray[0] = "gtrd3455";
yourArray[1] = "ltzy96545";
yourArray[2] = "lopa475";

Arrays.sort(yourArray, new Comparator<String>() {
    public int compare(String str1, String str2) {
        String substr1 = str1.substring(4);
        String substr2 = str2.substring(4);

        return Integer.valueOf(substr2).compareTo(Integer.valueOf(substr1));
    }
});

System.out.println(Arrays.toString(yourArray));

OUTPUT: -

[ltzy96545, gtrd3455, lopa475]
share|improve this answer
    
@NullUserException. Also You missed a valid error though. I used compareTo on Integer.parseInt. which returns primitive int. ;) –  Rohit Jain Oct 24 '12 at 19:42
    
@NullUserException. Aww!! Man, you got me. Slipped from my mind.. –  Rohit Jain Oct 24 '12 at 19:44
    
@NullUserException. Edited :) –  Rohit Jain Oct 24 '12 at 19:45
    
How can I read in lines of a text file and add each line to the string array? Then do the sorting based on that dynamic array. –  Jsn0605 Oct 26 '12 at 12:46
    
@Jsn0605 For that you need to first fill your Array from the text file. And then the remaining process is same. –  Rohit Jain Oct 26 '12 at 12:47

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