Created
May 18, 2015 22:45
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Miscellaneous helper functions to work with Enumerations
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| public static class IterTools | |
| { | |
| private static readonly Random Random = new Random(); | |
| /// <summary> | |
| /// Make an enumeration with a single element. | |
| /// </summary> | |
| /// <typeparam name="T">The type of the enumeration elements.</typeparam> | |
| /// <param name="element">The single element to enumerate.</param> | |
| /// <returns>A reference to the enumeration.</returns> | |
| public static IEnumerable<T> ToAtom<T>(this T element) | |
| { | |
| yield return element; | |
| } | |
| /// <summary> | |
| /// Splits an enumeration into fixed length partitions. | |
| /// </summary> | |
| /// <typeparam name="T">The enumeration type.</typeparam> | |
| /// <param name="source">The source enumeration.</param> | |
| /// <param name="size">The maximum size of each partition.</param> | |
| /// <returns>A reference to the enumeration.</returns> | |
| /// <exception cref="NullReferenceException">If <paramref name="source"/> is null.</exception> | |
| public static IEnumerable<T[]> Parititon<T>(this IEnumerable<T> source, int size) | |
| { | |
| return PartitionHelper(source, size); | |
| } | |
| /// <summary> | |
| /// Splits a sequence of chars into fixed length strings. | |
| /// </summary> | |
| /// <param name="source">The source enumeration.</param> | |
| /// <param name="size">The maximum size of each partition.</param> | |
| /// <returns>A reference to the enumeration.</returns> | |
| /// <exception cref="NullReferenceException">If <paramref name="source"/> is null.</exception> | |
| public static IEnumerable<string> Parititon(this IEnumerable<char> source, int size) | |
| { | |
| return PartitionHelper(source, size).Select(x => new string(x)); | |
| } | |
| /// <summary> | |
| /// Picks random elements out of an enumeration. | |
| /// </summary> | |
| /// <typeparam name="T">The enumeration type.</typeparam> | |
| /// <param name="source">The source enumeration.</param> | |
| /// <param name="count">The maximum number of items to return.</param> | |
| /// <returns>A reference to the enumeration.</returns> | |
| /// <exception cref="NullReferenceException">If <paramref name="source"/> is null.</exception> | |
| public static IEnumerable<T> Sample<T>(this IEnumerable<T> source, int count) | |
| { | |
| return source.Select(item => new { Key = Random.NextDouble(), Value = item }) | |
| .OrderBy(pair => pair.Key) | |
| .Take(count) | |
| .Select(pair => pair.Value); | |
| } | |
| private static IEnumerable<T[]> PartitionHelper<T>(IEnumerable<T> items, int size) | |
| { | |
| return items.Select((value, index) => new { value, index }) | |
| .GroupBy(x => x.index / size) | |
| .Select(x => x.Select(v => v.value).ToArray()); | |
| } | |
| } |
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