Sort a List by one of T's property

Question

I have a List<T>

How can I sort it ascendingly by one of T's int property?

I'm aware that I could create my own method to this manually but is there any way to this concisely like List<T>.Sort( by T's int property ); ?

Do you mean generically sort by a property, or just a general `List` that you have full access too? — LukeHennerley, May 07 '13 at 11:14

Ravi Gadag · Accepted Answer · 2013-05-07T11:24:29.897

6

you can use Enumerable Orderby to sort by it's property.

List<yourType> yourCollection = YourSourceList.OrderBy(e=>e.YourProperty).ToList();

edited May 07 '13 at 11:24

answered May 07 '13 at 11:13

Ravi Gadag

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@TimSchmelter thanks for your feed back. I changed it. it's not LINQ. it's simple Enumerable class. – Ravi Gadag May 07 '13 at 11:25
`Enumerable.OrderBy` and `ToList` are Linq methods and `ToList` creates a new `List` even if there's already one. The purpose of `List.Sort` (or `Array.Sort`) is to avoid creating an new collecton because that doubles the required memory(temporarily): – Tim Schmelter May 07 '13 at 11:27
@TimSchmelter that i know. ToList() creates new one. Sort() will do alter in the same List. so Sort is Efficient. – Ravi Gadag May 07 '13 at 11:28
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Linq is what's sitting in it's namespace and `Enumerable` is part of the `System.Linq` namespace. It's `Linq-To-Objects`. – Tim Schmelter May 07 '13 at 11:34

score 5 · Answer 2 · answered May 07 '13 at 11:14

5

Yes, you can use List<T>.Sort:

list.Sort((t1, t2) => t1.IntProperty.CompareTo(t2.IntProperty));

A less efficient but more readable approach is using Enumerable.OrderBy:

list = list.OrderBy(t => t.IntProperty).ToList();

answered May 07 '13 at 11:14

Tim Schmelter

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Who wants to comment the downvote? – Tim Schmelter May 07 '13 at 11:22
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3 downvotes for a correct answer? wtf? – sloth May 07 '13 at 11:35
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+1 voted up for the good answer and to reduce the Downvote effects :) – Ravi Gadag Jul 15 '13 at 12:38

score 2 · Answer 3 · answered May 07 '13 at 11:15

2

Try this:

 List<T> lst=List<T>.OrderBy(x => x.Property).ToList();

answered May 07 '13 at 11:15

Praveen VR

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score 1 · Answer 4 · answered May 07 '13 at 11:24

1

You could write your own Comparer class. And then sort using that class e.g:

myList.Sort(new MyListComparer());

answered May 07 '13 at 11:24

PHP Rocks

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score 0 · Answer 5 · answered May 07 '13 at 11:16

0

Hey Try This code to your list for sorting ASC/DESC

 List<HRDocumentCheckList> ser=new List<HRDocumentCheckList>();
 ser.OrderByDescending(q => q.Document.Id).ToList();

Hope it helps you

answered May 07 '13 at 11:16

Neeraj Dubey

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score 0 · Answer 6 · answered May 07 '13 at 11:44

For folks who doesn't have the privilege to use Lamda expression approach, which was accepted as answer can follow the below given approach. The core idea is to implement IComparable<Person> whereby checking any specific property/field defined within object and here it is 'Person'.

public class ConsoleApp
    {
        private static void Main(string[] args)
        {
            List<Person> p = new List<Person>();
            p.Add(new Person() {Age = 25, Name = "Jo"});
            p.Add(new Person() {Age = 10, Name = "Jo"});
            p.Add(new Person() {Age = 2, Name = "Jo"});
            p.Sort();

        }
    }

    public class Person : IComparable<Person>
    {
        public string Name { get; set; }
        public int Age { get; set; }

        public int CompareTo(Person other)
        {
            return other == null ? 1 : Age.CompareTo(other.Age);
        }
    }

Sort a List by one of T's property

6 Answers6