mirror of https://github.com/abpframework/abp.git
6 changed files with 128 additions and 7 deletions
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using System; |
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using System.Collections.Generic; |
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using System.Linq; |
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using JetBrains.Annotations; |
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namespace Volo.Abp |
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{ |
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/// <summary>
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/// A shortcut to use <see cref="Random"/> class.
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/// Also provides some useful methods.
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/// </summary>
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public static class RandomHelper |
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{ |
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private static readonly Random Rnd = new Random(); |
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/// <summary>
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/// Returns a random number within a specified range.
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/// </summary>
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/// <param name="minValue">The inclusive lower bound of the random number returned.</param>
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/// <param name="maxValue">The exclusive upper bound of the random number returned. maxValue must be greater than or equal to minValue.</param>
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/// <returns>
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/// A 32-bit signed integer greater than or equal to minValue and less than maxValue;
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/// that is, the range of return values includes minValue but not maxValue.
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/// If minValue equals maxValue, minValue is returned.
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/// </returns>
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public static int GetRandom(int minValue, int maxValue) |
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{ |
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lock (Rnd) |
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{ |
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return Rnd.Next(minValue, maxValue); |
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} |
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} |
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/// <summary>
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/// Returns a nonnegative random number less than the specified maximum.
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/// </summary>
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/// <param name="maxValue">The exclusive upper bound of the random number to be generated. maxValue must be greater than or equal to zero.</param>
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/// <returns>
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/// A 32-bit signed integer greater than or equal to zero, and less than maxValue;
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/// that is, the range of return values ordinarily includes zero but not maxValue.
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/// However, if maxValue equals zero, maxValue is returned.
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/// </returns>
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public static int GetRandom(int maxValue) |
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{ |
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lock (Rnd) |
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{ |
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return Rnd.Next(maxValue); |
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} |
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} |
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/// <summary>
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/// Returns a nonnegative random number.
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/// </summary>
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/// <returns>A 32-bit signed integer greater than or equal to zero and less than <see cref="int.MaxValue"/>.</returns>
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public static int GetRandom() |
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{ |
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lock (Rnd) |
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{ |
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return Rnd.Next(); |
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} |
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} |
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/// <summary>
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/// Gets random of given objects.
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/// </summary>
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/// <typeparam name="T">Type of the objects</typeparam>
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/// <param name="objs">List of object to select a random one</param>
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public static T GetRandomOf<T>([NotNull] params T[] objs) |
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{ |
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Check.NotNullOrEmpty(objs, nameof(objs)); |
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return objs[GetRandom(0, objs.Length)]; |
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} |
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/// <summary>
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/// Generates a randomized list from given enumerable.
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/// </summary>
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/// <typeparam name="T">Type of items in the list</typeparam>
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/// <param name="items">items</param>
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public static List<T> GenerateRandomizedList<T>([NotNull] IEnumerable<T> items) |
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{ |
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Check.NotNull(items, nameof(items)); |
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var currentList = new List<T>(items); |
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var randomList = new List<T>(); |
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while (currentList.Any()) |
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{ |
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var randomIndex = RandomHelper.GetRandom(0, currentList.Count); |
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randomList.Add(currentList[randomIndex]); |
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currentList.RemoveAt(randomIndex); |
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} |
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return randomList; |
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} |
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} |
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} |
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