https://twitter.com/davidfowl/status/1475235155308601357

JS_functional_to_CSharp_Linq.cs

using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
    public static void Main(string[] args)
    {
        var mapResult = new string[] {"🐕", "🐕", "🐕", "🐕"}.Select(e => "🐶");
        PrintEnumerable(mapResult);

        var filterResult = new string[] {"🐕", "🐶", "🐕", "🐕"}.Where(e => e == "🐶");
        PrintEnumerable(filterResult);

        var everyResult = new string[] {"🐕", "🐕", "🐶", "🐕"}.All(e => e == "🐶");
        Console.WriteLine(everyResult);

        var someResult = new string[] {"🐕", "🐶", "🐶", "🐕"}.Any(e => e == "🐶");
        Console.WriteLine(someResult);

        var fillResult = new string[] {"🐕", "🐕", "🐕", "🐕"}.Select((e, i) => i > 0 ? "🐶" : e);
        PrintEnumerable(fillResult);

        var findIndexResult = new string[] {"🐕", "🐕", "🐶", "🐕"}.TakeWhile(e => e != "🐶").Count();
        Console.WriteLine(findIndexResult);

        var findResult = new string[] {"🐕", "🐶", "🐕", "🐕"}.First(e => e == "🐶");
        Console.WriteLine(findResult);
        
        var reduceResult = new string[] {"🥒", "🍅", "🍞", "🧀"}.Aggregate((acc, cur) => $"{acc}{cur}"); // you can't actually turn these four emoji into 🍔
        Console.WriteLine(reduceResult);
    }

    public static void PrintEnumerable(IEnumerable<string> arr)
    {
        Console.WriteLine(string.Join("", arr));
    }
}