DCGO/Assets/Scripts/IEnumerableExtension.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using UnityEngine;

public static class IEnumerableExtension
{
    #region Get random element from list
    public static IEnumerable<T> GetRandom<T>(this IEnumerable<T> list, int count)
    {
        var random = new System.Random();

        var indexList = new List<int>();
        for (int i = 0; i < list.ToList().Count; i++)
        {
            indexList.Add(i);
        }

        for (int i = 0; i < count; i++)
        {
            int index = random.Next(0, indexList.Count);
            int value = indexList[index];
            indexList.RemoveAt(index);
            yield return list.ToList()[value];
        }
    }
    #endregion

    #region Map
    public static List<U> Map<T, U>(this List<T> list, Func<T, U> getElement)
    {
        return list.Select(x => getElement(x)).ToList();
    }

    public static U[] Map<T, U>(this T[] array, Func<T, U> getElement)
    {
        return array.Select(x => getElement(x)).ToArray();
    }
    #endregion

    #region Filter
    public static List<T> Filter<T>(this List<T> list, Func<T, bool> getElement)
    {
        return list.Where(x => getElement(x)).ToList();
    }

    public static T[] Filter<T>(this T[] array, Func<T, bool> getElement)
    {
        return array.Where(x => getElement(x)).ToArray();
    }
    #endregion

    #region Some
    public static bool Some<T>(this IEnumerable<T> list, Func<T, bool> getElement)
    {
        return list.Any(x => getElement(x));
    }
    #endregion

    #region Flat
    public static List<T> Flat<T>(this List<List<T>> list)
    {
        return list.SelectMany(x => x).ToList();
    }

    public static T[] Flat<T>(this T[][] array)
    {
        return array.SelectMany(x => x).ToArray();
    }
    #endregion

    #region Reduce
    public static T Reduce<T>(this IEnumerable<T> list, Func<T, T, T> getResult)
    {
        return list.Aggregate(getResult);
    }
    #endregion

    #region Clone
    public static List<T> Clone<T>(this List<T> list)
    {
        return list.Map(x => x).ToList();
    }

    public static T[] CloneArray<T>(this T[] array)
    {
        return array.Map(x => x).ToArray();
    }
    #endregion

    #region Every
    public static bool Every<T>(this IEnumerable<T> list, Func<T, bool> getElement)
    {
        return list.All(x => getElement(x));
    }
    #endregion
}