Example #1
0
        public TElement Last(Func <TElement, bool> predicate)
        {
            CachingComparer <TElement> comparer = GetComparer();

            using (IEnumerator <TElement> e = source.GetEnumerator())
            {
                TElement value;
                do
                {
                    if (!e.MoveNext())
                    {
                        throw Error.NoMatch();
                    }
                    value = e.Current;
                } while (!predicate(value));
                comparer.SetElement(value);
                while (e.MoveNext())
                {
                    TElement x = e.Current;
                    if (predicate(x) && comparer.Compare(x, false) >= 0)
                    {
                        value = x;
                    }
                }
                return(value);
            }
        }
Example #2
0
        public static TSource First <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate)
        {
            if (source == null)
            {
                throw Error.ArgumentNull("source");
            }
            if (predicate == null)
            {
                throw Error.ArgumentNull("predicate");
            }
            OrderedEnumerable <TSource> ordered = source as OrderedEnumerable <TSource>;

            if (ordered != null)
            {
                return(ordered.First(predicate));
            }
            foreach (TSource element in source)
            {
                if (predicate(element))
                {
                    return(element);
                }
            }
            throw Error.NoMatch();
        }
Example #3
0
        public static TSource Single <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate)
        {
            if (source == null)
            {
                throw Error.ArgumentNull(nameof(source));
            }

            if (predicate == null)
            {
                throw Error.ArgumentNull(nameof(predicate));
            }

            using (IEnumerator <TSource> e = source.GetEnumerator())
            {
                while (e.MoveNext())
                {
                    TSource result = e.Current;
                    if (predicate(result))
                    {
                        while (e.MoveNext())
                        {
                            if (predicate(e.Current))
                            {
                                throw Error.MoreThanOneMatch();
                            }
                        }

                        return(result);
                    }
                }
            }

            throw Error.NoMatch();
        }
Example #4
0
        public static TSource Last <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate)
        {
            if (source == null)
            {
                throw Error.ArgumentNull(nameof(source));
            }

            if (predicate == null)
            {
                throw Error.ArgumentNull(nameof(predicate));
            }

            OrderedEnumerable <TSource> ordered = source as OrderedEnumerable <TSource>;

            if (ordered != null)
            {
                return(ordered.Last(predicate));
            }

            IList <TSource> list = source as IList <TSource>;

            if (list != null)
            {
                for (int i = list.Count - 1; i >= 0; --i)
                {
                    TSource result = list[i];
                    if (predicate(result))
                    {
                        return(result);
                    }
                }
            }
            else
            {
                using (IEnumerator <TSource> e = source.GetEnumerator())
                {
                    while (e.MoveNext())
                    {
                        TSource result = e.Current;
                        if (predicate(result))
                        {
                            while (e.MoveNext())
                            {
                                TSource element = e.Current;
                                if (predicate(element))
                                {
                                    result = element;
                                }
                            }

                            return(result);
                        }
                    }
                }
            }

            throw Error.NoMatch();
        }
Example #5
0
        public static TSource First <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate)
        {
            TSource first = source.TryGetFirst(predicate, out bool found);

            if (!found)
            {
                throw Error.NoMatch();
            }

            return(first);
        }
Example #6
0
        public static TSource Last <TSource>(this IEnumerable <TSource> source, Func <TSource, bool> predicate)
        {
            bool    found;
            TSource last = source.TryGetLast(predicate, out found);

            if (!found)
            {
                throw Error.NoMatch();
            }

            return(last);
        }