CODEWITHSUNDEEP
javaandroidarrayssortingarraylist
Ajay Venugopal
Ajay Venugopal

Reputation: 1710

Sort Arraylist contains file path

I need to sort this array with filename, each item is from different path.

how do i sort this array based on file names.

ArrayList<String> sort = new ArrayList<>();

        sort.add("/etc/fest/gerts.png");
        sort.add("/etc/fest/ase.png");
        sort.add("/etc/test/zer.png");
        sort.add("/etc/fest/dse.png");

Upvotes: 2

Views: 2694

Answers (4)

mhasan
mhasan

Reputation: 3709

You can do something like this in Java 8:

Here in this it will first get the file names by substringing the string based on last index of "/". And then sort based on the same.

list.sort(Comparator
    .comparing(s -> s.substring(s.lastIndexOf("/") + 1))

In case you are not on Java 8. You can create a custom Comparator like this and then call the Collections API.

public class SubstringComparator implements Comparator {
  public int compare(Object o1, Object o2) {
    String s1 = o1.tostring().substring(o1.tostring().lastIndexOf("/") + 1);
    String s2 = o2.tostring().substring(o2.tostring().lastIndexOf("/") + 1);
    return s1.compareTo(s2);
    // or, more concisely:
    // return o1.toString().substring(1).equals(o2.toString().substring(1));
  }
}

And then call it as below:

SubstringComparator comparator = new SubstringComparator();
Collections.sort(list, comparator );

Upvotes: 2

Mateus Viccari
Mateus Viccari

Reputation: 7709

This will sort only by the file names, ignoring the parent folders:

Using JAVA 8

sort.sort(Comparator.comparing(o -> new File(o).getName().toUpperCase()));
sort.forEach(System.out::println);

Using JAVA < 8

sort.sort(new Comparator<String>() {
    @Override
    public int compare(String o1, String o2) {
        return new File(o1).getName().toUpperCase().compareTo(new File(o2).getName().toUpperCase());
    }
});
for (String s : sort) {
    System.out.println(s);
}

This will produce the following output:

/etc/fest/ase.png
/etc/fest/dse.png
/etc/fest/gerts.png
/etc/test/zer.png

Upvotes: 1

Arun Shankar
Arun Shankar

Reputation: 2593

Try this code:

Collections.sort(sort);

Upvotes: 1

Yamen Nassif
Yamen Nassif

Reputation: 2476

you can use the Collection method sort

Collections.sort(sort);

Upvotes: 0

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