Language-ext: Filtering out None properties from collection

[buinauskas]

Hello, I'd appreciate some help. I have a collection of items that have optional properties. What is the correct way to filter only those items that actually are in Some state? This is a test case I came up with:

using FluentAssertions;
using LanguageExt;
using System;
using System.Collections.Generic;
using Xunit;
using static LanguageExt.Prelude;

namespace OptionCollectionTest
{
    public class UnitTest1
    {
        [Fact]
        public void Test1()
        {
            var todos = new List<Todo>
            {
                new Todo { Id = 1, Description = None },
                new Todo { Id = 2, Description = Some("This is a description of Todo(2)") },
                new Todo { Id = 3, Description = Some("This is a description of Todo(3)") }
            };

            var expectedDescriptions = new List<string>
            {
                "This is a description of Todo(2)",
                "This is a description of Todo(3)"
            };

            var actualDescriptions = GetDescriptions(todos);

            actualDescriptions.Should().BeEquivalentTo(expectedDescriptions);
        }

        private IEnumerable<string> GetDescriptions(IEnumerable<Todo> todos)
        {
            throw new NotImplementedException();
        }

        private class Todo
        {
            public int Id { get; set; }
            public Option<string> Description { get; set; }
        }
    }
}

I did some reading on how to filter out None (Nothing) values from lists in Elm/F# and some of them have indicated usage of identity function, but I was not able to figure out how to apply it to this library.

[TysonMN]

Try todos.Somes()

[tanxeel90]

For the specific test case, todos.Map(t => t.Description).Somes()

[buinauskas]

I'm an idiot :)

Thank you both!

[TysonMN]

No need to be too hard on yourself. It is only obvious once you have seen it for the first time.