IEnumerables to EngFormat ({0}, {1}, and/or {2})

        private static string HandleEngFormat(string word, List<string> list)
        {
            switch (list.Count)
            {
                case 0:
                    return string.Empty;
                case 1:
                    return list[0];
                case 2:
                    return list[0] + " " + word + " " + list[1];
                default:
                    if (list.Count < 0)
                    {
                        throw new Exception("count is less than 0.");
                    }
                    int last = list.Count - 1;
                    list[last] = word + " " + list[last];
                    string output = list[0];
                    for (int i = 1; i < list.Count; i++)
                    {
                        output += ", " + list[i];
                    }
                    return output;
            }
        }

        public static string ToEngFormat<T>(this IEnumerable<T> collection, string word = "and")
        {
            List<string> list = new List<string>();
            if (typeof(T).IsValueType)
            {
                string conv;
                foreach (T item in collection)
                {
                    if (!string.IsNullOrEmpty(conv = item.ToString()))
                    {
                        list.Add(conv);
                    }
                }
                list = new List<string>(collection.Select(item => item.ToString()));
            }
            else
            {
                string conv;
                foreach (T item in collection)
                {
                    if (item != null && !string.IsNullOrEmpty(conv = item.ToString()))
                    {
                        list.Add(conv);
                    }
                }
            }
            return HandleEngFormat(word, list);
        }

        public static string ToEngFormat<T>(this IEnumerable<T> collection, string word, Func<T, bool> where)
        {
            List<string> list = new List<string>();
            if (typeof(T).IsValueType)
            {
                string conv;
                foreach (T item in collection)
                {
                    if (where(item) && !string.IsNullOrEmpty(conv = item.ToString()))
                    {
                        list.Add(conv);
                    }
                }
            }
            else
            {
                string conv;
                foreach (T item in collection)
                {
                    if (item != null && where(item) && !string.IsNullOrEmpty(conv = item.ToString()))
                    {
                        list.Add(conv);
                    }
                }
            }
            return HandleEngFormat(word, list);
        }

        public static string ToEngFormat<T>(this IEnumerable<T> collection, string word, Func<T, string> select)
        {
            List<string> list = new List<string>();
            if (typeof(T).IsValueType)
            {
                string conv;
                foreach (T item in collection)
                {
                    if (!string.IsNullOrEmpty(conv = select(item)))
                    {
                        list.Add(conv);
                    }
                }
            }
            else
            {
                string conv;
                foreach (T item in collection)
                {
                    if (item != null && !string.IsNullOrEmpty(conv = select(item)))
                    {
                        list.Add(conv);
                    }
                }
            }
            return HandleEngFormat(word, list);
        }

        public static string ToEngFormat<T>(this IEnumerable<T> collection, string word, Func<T, bool> where, Func<T, string> select)
        {
            List<string> list = new List<string>();
            if (typeof(T).IsValueType)
            {
                string conv;
                foreach (T item in collection)
                {
                    if (where(item) && !string.IsNullOrEmpty(conv = select(item)))
                    {
                        list.Add(conv);
                    }
                }
            }
            else
            {
                string conv;
                foreach (T item in collection)
                {
                    if (item != null && where(item) && !string.IsNullOrEmpty(conv = select(item)))
                    {
                        list.Add(conv);
                    }
                }
            }
            return HandleEngFormat(word, list);
        }

        public static string ToEngFormat<T, T2>(this IEnumerable<T> collection, string word, Func<T, T2> select, Func<T2, bool> where)
        {
            T2 ykno;
            List<string> list = new List<string>();
            if (typeof(T).IsValueType)
            {
                foreach (T item in collection)
                {
                    ykno = select(item);
                    if (where(ykno))
                    {
                        list.Add(ykno.ToString());
                    }
                }
            }
            else
            {
                string conv;
                foreach (T item in collection)
                {
                    if (item == null || (ykno = select(item)) == null)
                    {
                        continue;
                    }
                    if (where(ykno) && !string.IsNullOrEmpty(conv = ykno.ToString()))
                    {
                        list.Add(conv);
                    }
                }
            }
            return HandleEngFormat(word, list);
        }

        public static string ToEngFormat<T, T2>(this IEnumerable<T> collection, string word, Func<T, T2> select, Func<T2, bool> where, Func<T2, string> select2)
        {
            T2 ykno;
            string ykno2;
            List<string> list = new List<string>();
            if (typeof(T).IsValueType)
            {
                foreach (T item in collection)
                {
                    ykno = select(item);
                    if (where(ykno) && !string.IsNullOrEmpty(ykno2 = select2(ykno)))
                    {
                        list.Add(ykno2);
                    }
                }
            }
            else
            {
                foreach (T item in collection)
                {
                    if (item == null || (ykno = select(item)) == null)
                    {
                        continue;
                    }
                    if (where(ykno) && !string.IsNullOrEmpty(ykno2 = select2(ykno)))
                    {
                        list.Add(ykno2);
                    }
                }
            }
            return HandleEngFormat(word, list);
        }