CODEWITHSUNDEEP
c#.net
Oscar vs
Oscar vs

Reputation: 386

How to sort numbered filenames in list in C#

I try to sort a list that contains filepaths. And I want them to be sorted by the numbers in them.

With the given code I use I don't get the expected result.

var mylist = mylist.OrderBy(x => int.Parse(Regex.Replace(x, "[^0-9]+", "0"))).ToList<string>();

I expect the result to be:

c:\somedir\1.jpg
c:\somedir\2.jpg
c:\somedir\3.jpg
c:\somedir\7.jpg
c:\somedir\8.jpg
c:\somedir\9.jpg
c:\somedir\10.jpg
c:\somedir\12.jpg
c:\somedir\20.jpg

But the output is random.

Upvotes: 0

Views: 98

Answers (2)

Just Shadow
Just Shadow

Reputation: 11921

There is a simple way of achieving that. Let's say you have a string list like this:

List<string> allThePaths = new List<string>()
{
    "c:\\somedir\\1.jpg",
    "c:\\somedir\\2.jpg",
    "c:\\somedir\\20.jpg",
    "c:\\somedir\\7.jpg",
    "c:\\somedir\\12.jpg",
    "c:\\somedir\\8.jpg",
    "c:\\somedir\\9.jpg",
    "c:\\somedir\\3.jpg",
    "c:\\somedir\\10.jpg"
};

You can get the desired result with this:

List<string> sortedPaths = allThePaths
    .OrderBy(stringItem => stringItem.Length)
    .ThenBy(stringItem => stringItem).ToList();

Note: Also make sure you've included LINQ:

using System.Linq;

Here is a demo example just in case it's needed.

More complex solutions can be found there.

Upvotes: 4

blenderfreaky
blenderfreaky

Reputation: 768

A cleaner way of doing this would be to use System.IO.Path:

public IEnumerable<string> OrderFilesByNumberedName(IEnumerable<string> unsortedPathList) =>
    unsortedPathList
    .Select(path => new { name = Path.GetFileNameWithoutExtension(path), path }) // Get filename
    .OrderBy(file => int.Parse(file.name)) // Sort by number
    .Select(file => file.path); // Return only path

Upvotes: 0

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