IEnumerableExtensions.cs 34 KB

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  1. #nullable enable
  2. using System;
  3. using System.Collections.Concurrent;
  4. using System.Collections.Generic;
  5. using System.Diagnostics;
  6. using System.Linq;
  7. using System.Linq.Expressions;
  8. using System.Threading;
  9. using System.Threading.Tasks;
  10. namespace Masuit.Tools
  11. {
  12. public static partial class IEnumerableExtensions
  13. {
  14. /// <summary>
  15. /// 按字段属性判等取交集
  16. /// </summary>
  17. /// <typeparam name="TFirst"></typeparam>
  18. /// <typeparam name="TSecond"></typeparam>
  19. /// <param name="second"></param>
  20. /// <param name="condition"></param>
  21. /// <param name="first"></param>
  22. /// <returns></returns>
  23. public static IEnumerable<TFirst> IntersectBy<TFirst, TSecond>(this IEnumerable<TFirst> first, IEnumerable<TSecond> second, Func<TFirst, TSecond, bool> condition)
  24. {
  25. return first.Where(f => second.Any(s => condition(f, s)));
  26. }
  27. /// <summary>
  28. /// 按字段属性判等取差集
  29. /// </summary>
  30. /// <typeparam name="TFirst"></typeparam>
  31. /// <typeparam name="TSecond"></typeparam>
  32. /// <param name="second"></param>
  33. /// <param name="condition"></param>
  34. /// <param name="first"></param>
  35. /// <returns></returns>
  36. public static IEnumerable<TFirst> ExceptBy<TFirst, TSecond>(this IEnumerable<TFirst> first, IEnumerable<TSecond> second, Func<TFirst, TSecond, bool> condition)
  37. {
  38. return first.Where(f => !second.Any(s => condition(f, s)));
  39. }
  40. #if NET6_0
  41. #else
  42. /// <summary>
  43. /// 按字段去重
  44. /// </summary>
  45. /// <typeparam name="TSource"></typeparam>
  46. /// <typeparam name="TKey"></typeparam>
  47. /// <param name="source"></param>
  48. /// <param name="keySelector"></param>
  49. /// <returns></returns>
  50. public static IEnumerable<TSource> DistinctBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
  51. {
  52. var hash = new HashSet<TKey>();
  53. return source.Where(p => hash.Add(keySelector(p)));
  54. }
  55. /// <summary>
  56. /// 按字段属性判等取交集
  57. /// </summary>
  58. /// <typeparam name="TSource"></typeparam>
  59. /// <typeparam name="TKey"></typeparam>
  60. /// <param name="first"></param>
  61. /// <param name="second"></param>
  62. /// <param name="keySelector"></param>
  63. /// <returns></returns>
  64. public static IEnumerable<TSource> IntersectBy<TSource, TKey>(this IEnumerable<TSource> first, IEnumerable<TKey> second, Func<TSource, TKey> keySelector)
  65. {
  66. return first.IntersectBy(second, keySelector, null);
  67. }
  68. /// <summary>
  69. /// 按字段属性判等取交集
  70. /// </summary>
  71. /// <typeparam name="TSource"></typeparam>
  72. /// <typeparam name="TKey"></typeparam>
  73. /// <param name="first"></param>
  74. /// <param name="second"></param>
  75. /// <param name="keySelector"></param>
  76. /// <returns></returns>
  77. public static IEnumerable<TSource> IntersectBy<TSource, TKey>(this IEnumerable<TSource> first, IEnumerable<TKey> second, Func<TSource, TKey> keySelector, IEqualityComparer<TKey>? comparer)
  78. {
  79. if (first == null)
  80. throw new ArgumentNullException(nameof(first));
  81. if (second == null)
  82. throw new ArgumentNullException(nameof(second));
  83. if (keySelector == null)
  84. throw new ArgumentNullException(nameof(keySelector));
  85. return IntersectByIterator(first, second, keySelector, comparer);
  86. }
  87. private static IEnumerable<TSource> IntersectByIterator<TSource, TKey>(IEnumerable<TSource> first, IEnumerable<TKey> second, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
  88. {
  89. var set = new HashSet<TKey>(second, comparer);
  90. foreach (var source in first)
  91. {
  92. if (set.Remove(keySelector(source)))
  93. yield return source;
  94. }
  95. }
  96. /// <summary>
  97. /// 按字段属性判等取差集
  98. /// </summary>
  99. /// <typeparam name="TSource"></typeparam>
  100. /// <typeparam name="TKey"></typeparam>
  101. /// <param name="first"></param>
  102. /// <param name="second"></param>
  103. /// <param name="keySelector"></param>
  104. /// <returns></returns>
  105. public static IEnumerable<TSource> ExceptBy<TSource, TKey>(this IEnumerable<TSource> first, IEnumerable<TKey> second, Func<TSource, TKey> keySelector)
  106. {
  107. return first.ExceptBy(second, keySelector, null);
  108. }
  109. /// <summary>
  110. /// 按字段属性判等取差集
  111. /// </summary>
  112. /// <typeparam name="TSource"></typeparam>
  113. /// <typeparam name="TKey"></typeparam>
  114. /// <param name="first"></param>
  115. /// <param name="second"></param>
  116. /// <param name="keySelector"></param>
  117. /// <param name="comparer"></param>
  118. /// <returns></returns>
  119. /// <exception cref="ArgumentNullException"></exception>
  120. public static IEnumerable<TSource> ExceptBy<TSource, TKey>(this IEnumerable<TSource> first, IEnumerable<TKey> second, Func<TSource, TKey> keySelector, IEqualityComparer<TKey>? comparer)
  121. {
  122. if (first == null)
  123. throw new ArgumentNullException(nameof(first));
  124. if (second == null)
  125. throw new ArgumentNullException(nameof(second));
  126. if (keySelector == null)
  127. throw new ArgumentNullException(nameof(keySelector));
  128. return ExceptByIterator(first, second, keySelector, comparer);
  129. }
  130. private static IEnumerable<TSource> ExceptByIterator<TSource, TKey>(IEnumerable<TSource> first, IEnumerable<TKey> second, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
  131. {
  132. var set = new HashSet<TKey>(second, comparer);
  133. foreach (var source in first)
  134. {
  135. if (set.Add(keySelector(source)))
  136. yield return source;
  137. }
  138. }
  139. #endif
  140. /// <summary>
  141. /// 添加多个元素
  142. /// </summary>
  143. /// <typeparam name="T"></typeparam>
  144. /// <param name="this"></param>
  145. /// <param name="values"></param>
  146. public static void AddRange<T>(this ICollection<T> @this, params T[] values)
  147. {
  148. foreach (var obj in values)
  149. {
  150. @this.Add(obj);
  151. }
  152. }
  153. /// <summary>
  154. /// 添加多个元素
  155. /// </summary>
  156. /// <typeparam name="T"></typeparam>
  157. /// <param name="this"></param>
  158. /// <param name="values"></param>
  159. public static void AddRange<T>(this ICollection<T> @this, IEnumerable<T> values)
  160. {
  161. foreach (var obj in values)
  162. {
  163. @this.Add(obj);
  164. }
  165. }
  166. /// <summary>
  167. /// 添加多个元素
  168. /// </summary>
  169. /// <typeparam name="T"></typeparam>
  170. /// <param name="this"></param>
  171. /// <param name="values"></param>
  172. public static void AddRange<T>(this ConcurrentBag<T> @this, params T[] values)
  173. {
  174. foreach (var obj in values)
  175. {
  176. @this.Add(obj);
  177. }
  178. }
  179. /// <summary>
  180. /// 添加多个元素
  181. /// </summary>
  182. /// <typeparam name="T"></typeparam>
  183. /// <param name="this"></param>
  184. /// <param name="values"></param>
  185. public static void AddRange<T>(this ConcurrentQueue<T> @this, params T[] values)
  186. {
  187. foreach (var obj in values)
  188. {
  189. @this.Enqueue(obj);
  190. }
  191. }
  192. /// <summary>
  193. /// 添加符合条件的多个元素
  194. /// </summary>
  195. /// <typeparam name="T"></typeparam>
  196. /// <param name="this"></param>
  197. /// <param name="predicate"></param>
  198. /// <param name="values"></param>
  199. public static void AddRangeIf<T>(this ICollection<T> @this, Func<T, bool> predicate, params T[] values)
  200. {
  201. foreach (var obj in values)
  202. {
  203. if (predicate(obj))
  204. {
  205. @this.Add(obj);
  206. }
  207. }
  208. }
  209. /// <summary>
  210. /// 添加符合条件的多个元素
  211. /// </summary>
  212. /// <typeparam name="T"></typeparam>
  213. /// <param name="this"></param>
  214. /// <param name="predicate"></param>
  215. /// <param name="values"></param>
  216. public static void AddRangeIf<T>(this ConcurrentBag<T> @this, Func<T, bool> predicate, params T[] values)
  217. {
  218. foreach (var obj in values)
  219. {
  220. if (predicate(obj))
  221. {
  222. @this.Add(obj);
  223. }
  224. }
  225. }
  226. /// <summary>
  227. /// 添加符合条件的多个元素
  228. /// </summary>
  229. /// <typeparam name="T"></typeparam>
  230. /// <param name="this"></param>
  231. /// <param name="predicate"></param>
  232. /// <param name="values"></param>
  233. public static void AddRangeIf<T>(this ConcurrentQueue<T> @this, Func<T, bool> predicate, params T[] values)
  234. {
  235. foreach (var obj in values)
  236. {
  237. if (predicate(obj))
  238. {
  239. @this.Enqueue(obj);
  240. }
  241. }
  242. }
  243. /// <summary>
  244. /// 添加不重复的元素
  245. /// </summary>
  246. /// <typeparam name="T"></typeparam>
  247. /// <param name="this"></param>
  248. /// <param name="values"></param>
  249. public static void AddRangeIfNotContains<T>(this ICollection<T> @this, params T[] values)
  250. {
  251. foreach (T obj in values)
  252. {
  253. if ([email protected](obj))
  254. {
  255. @this.Add(obj);
  256. }
  257. }
  258. }
  259. /// <summary>
  260. /// 移除符合条件的元素
  261. /// </summary>
  262. /// <typeparam name="T"></typeparam>
  263. /// <param name="this"></param>
  264. /// <param name="where"></param>
  265. public static void RemoveWhere<T>(this ICollection<T> @this, Func<T, bool> @where)
  266. {
  267. foreach (var obj in @this.Where(where).ToList())
  268. {
  269. @this.Remove(obj);
  270. }
  271. }
  272. /// <summary>
  273. /// 在元素之后添加元素
  274. /// </summary>
  275. /// <typeparam name="T"></typeparam>
  276. /// <param name="list"></param>
  277. /// <param name="condition">条件</param>
  278. /// <param name="value">值</param>
  279. public static void InsertAfter<T>(this IList<T> list, Func<T, bool> condition, T value)
  280. {
  281. foreach (var item in list.Select((item, index) => new
  282. {
  283. item,
  284. index
  285. }).Where(p => condition(p.item)).OrderByDescending(p => p.index))
  286. {
  287. if (item.index + 1 == list.Count)
  288. {
  289. list.Add(value);
  290. }
  291. else
  292. {
  293. list.Insert(item.index + 1, value);
  294. }
  295. }
  296. }
  297. /// <summary>
  298. /// 在元素之后添加元素
  299. /// </summary>
  300. /// <typeparam name="T"></typeparam>
  301. /// <param name="list"></param>
  302. /// <param name="index">索引位置</param>
  303. /// <param name="value">值</param>
  304. public static void InsertAfter<T>(this IList<T> list, int index, T value)
  305. {
  306. foreach (var item in list.Select((v, i) => new
  307. {
  308. Value = v,
  309. Index = i
  310. }).Where(p => p.Index == index).OrderByDescending(p => p.Index))
  311. {
  312. if (item.Index + 1 == list.Count)
  313. {
  314. list.Add(value);
  315. }
  316. else
  317. {
  318. list.Insert(item.Index + 1, value);
  319. }
  320. }
  321. }
  322. /// <summary>
  323. /// 转HashSet
  324. /// </summary>
  325. /// <typeparam name="T"></typeparam>
  326. /// <typeparam name="TResult"></typeparam>
  327. /// <param name="source"></param>
  328. /// <param name="selector"></param>
  329. /// <returns></returns>
  330. public static HashSet<TResult> ToHashSet<T, TResult>(this IEnumerable<T> source, Func<T, TResult> selector)
  331. {
  332. var set = new HashSet<TResult>();
  333. set.UnionWith(source.Select(selector));
  334. return set;
  335. }
  336. /// <summary>
  337. /// 遍历IEnumerable
  338. /// </summary>
  339. /// <param name="objs"></param>
  340. /// <param name="action">回调方法</param>
  341. /// <typeparam name="T"></typeparam>
  342. public static void ForEach<T>(this IEnumerable<T> objs, Action<T> action)
  343. {
  344. foreach (var o in objs)
  345. {
  346. action(o);
  347. }
  348. }
  349. /// <summary>
  350. /// 异步foreach
  351. /// </summary>
  352. /// <typeparam name="T"></typeparam>
  353. /// <param name="source"></param>
  354. /// <param name="maxParallelCount">最大并行数</param>
  355. /// <param name="action"></param>
  356. /// <param name="cancellationToken"></param>
  357. /// <returns></returns>
  358. public static async Task ForeachAsync<T>(this IEnumerable<T> source, Func<T, Task> action, int maxParallelCount, CancellationToken cancellationToken = default)
  359. {
  360. if (Debugger.IsAttached)
  361. {
  362. foreach (var item in source)
  363. {
  364. await action(item);
  365. }
  366. return;
  367. }
  368. var list = new List<Task>();
  369. foreach (var item in source)
  370. {
  371. if (cancellationToken.IsCancellationRequested)
  372. {
  373. return;
  374. }
  375. list.Add(action(item));
  376. if (list.Count >= maxParallelCount)
  377. {
  378. await Task.WhenAll(list);
  379. list.Clear();
  380. }
  381. }
  382. await Task.WhenAll(list);
  383. }
  384. /// <summary>
  385. /// 异步foreach
  386. /// </summary>
  387. /// <typeparam name="T"></typeparam>
  388. /// <param name="source"></param>
  389. /// <param name="action"></param>
  390. /// <returns></returns>
  391. public static Task ForeachAsync<T>(this IEnumerable<T> source, Func<T, Task> action, CancellationToken cancellationToken = default)
  392. {
  393. return ForeachAsync(source, action, source.Count(), cancellationToken);
  394. }
  395. /// <summary>
  396. /// 异步Select
  397. /// </summary>
  398. /// <typeparam name="T"></typeparam>
  399. /// <typeparam name="TResult"></typeparam>
  400. /// <param name="source"></param>
  401. /// <param name="selector"></param>
  402. /// <returns></returns>
  403. public static Task<TResult[]> SelectAsync<T, TResult>(this IEnumerable<T> source, Func<T, Task<TResult>> selector)
  404. {
  405. return Task.WhenAll(source.Select(selector));
  406. }
  407. /// <summary>
  408. /// 异步Select
  409. /// </summary>
  410. /// <typeparam name="T"></typeparam>
  411. /// <typeparam name="TResult"></typeparam>
  412. /// <param name="source"></param>
  413. /// <param name="selector"></param>
  414. /// <returns></returns>
  415. public static Task<TResult[]> SelectAsync<T, TResult>(this IEnumerable<T> source, Func<T, int, Task<TResult>> selector)
  416. {
  417. return Task.WhenAll(source.Select(selector));
  418. }
  419. /// <summary>
  420. /// 异步Select
  421. /// </summary>
  422. /// <typeparam name="T"></typeparam>
  423. /// <typeparam name="TResult"></typeparam>
  424. /// <param name="source"></param>
  425. /// <param name="selector"></param>
  426. /// <param name="maxParallelCount">最大并行数</param>
  427. /// <returns></returns>
  428. public static async Task<List<TResult>> SelectAsync<T, TResult>(this IEnumerable<T> source, Func<T, Task<TResult>> selector, int maxParallelCount)
  429. {
  430. var results = new List<TResult>();
  431. var tasks = new List<Task<TResult>>();
  432. foreach (var item in source)
  433. {
  434. var task = selector(item);
  435. tasks.Add(task);
  436. if (tasks.Count >= maxParallelCount)
  437. {
  438. results.AddRange(await Task.WhenAll(tasks));
  439. tasks.Clear();
  440. }
  441. }
  442. results.AddRange(await Task.WhenAll(tasks));
  443. return results;
  444. }
  445. /// <summary>
  446. /// 异步Select
  447. /// </summary>
  448. /// <typeparam name="T"></typeparam>
  449. /// <typeparam name="TResult"></typeparam>
  450. /// <param name="source"></param>
  451. /// <param name="selector"></param>
  452. /// <param name="maxParallelCount">最大并行数</param>
  453. /// <returns></returns>
  454. public static async Task<List<TResult>> SelectAsync<T, TResult>(this IEnumerable<T> source, Func<T, int, Task<TResult>> selector, int maxParallelCount)
  455. {
  456. var results = new List<TResult>();
  457. var tasks = new List<Task<TResult>>();
  458. int index = 0;
  459. foreach (var item in source)
  460. {
  461. var task = selector(item, index++);
  462. tasks.Add(task);
  463. if (tasks.Count >= maxParallelCount)
  464. {
  465. results.AddRange(await Task.WhenAll(tasks));
  466. tasks.Clear();
  467. }
  468. }
  469. results.AddRange(await Task.WhenAll(tasks));
  470. return results;
  471. }
  472. /// <summary>
  473. /// 异步For
  474. /// </summary>
  475. /// <typeparam name="T"></typeparam>
  476. /// <param name="source"></param>
  477. /// <param name="selector"></param>
  478. /// <param name="maxParallelCount">最大并行数</param>
  479. /// <param name="cancellationToken">取消口令</param>
  480. /// <returns></returns>
  481. public static async Task ForAsync<T>(this IEnumerable<T> source, Func<T, int, Task> selector, int maxParallelCount, CancellationToken cancellationToken = default)
  482. {
  483. int index = 0;
  484. if (Debugger.IsAttached)
  485. {
  486. foreach (var item in source)
  487. {
  488. await selector(item, index);
  489. index++;
  490. }
  491. return;
  492. }
  493. var list = new List<Task>();
  494. foreach (var item in source)
  495. {
  496. if (cancellationToken.IsCancellationRequested)
  497. {
  498. return;
  499. }
  500. list.Add(selector(item, index));
  501. Interlocked.Add(ref index, 1);
  502. if (list.Count >= maxParallelCount)
  503. {
  504. await Task.WhenAll(list);
  505. list.Clear();
  506. }
  507. }
  508. await Task.WhenAll(list);
  509. }
  510. /// <summary>
  511. /// 异步For
  512. /// </summary>
  513. /// <typeparam name="T"></typeparam>
  514. /// <param name="source"></param>
  515. /// <param name="selector"></param>
  516. /// <param name="cancellationToken">取消口令</param>
  517. /// <returns></returns>
  518. public static Task ForAsync<T>(this IEnumerable<T> source, Func<T, int, Task> selector, CancellationToken cancellationToken = default)
  519. {
  520. return ForAsync(source, selector, source.Count(), cancellationToken);
  521. }
  522. /// <summary>
  523. /// 取最大值
  524. /// </summary>
  525. /// <typeparam name="TSource"></typeparam>
  526. /// <typeparam name="TResult"></typeparam>
  527. /// <param name="source"></param>
  528. /// <param name="selector"></param>
  529. /// <returns></returns>
  530. public static TResult MaxOrDefault<TSource, TResult>(this IQueryable<TSource> source, Expression<Func<TSource, TResult>> selector) => source.Select(selector).DefaultIfEmpty().Max();
  531. /// <summary>
  532. /// 取最大值
  533. /// </summary>
  534. /// <typeparam name="TSource"></typeparam>
  535. /// <typeparam name="TResult"></typeparam>
  536. /// <param name="source"></param>
  537. /// <param name="selector"></param>
  538. /// <param name="defaultValue"></param>
  539. /// <returns></returns>
  540. public static TResult MaxOrDefault<TSource, TResult>(this IQueryable<TSource> source, Expression<Func<TSource, TResult>> selector, TResult defaultValue) => source.Select(selector).DefaultIfEmpty(defaultValue).Max();
  541. /// <summary>
  542. /// 取最大值
  543. /// </summary>
  544. /// <typeparam name="TSource"></typeparam>
  545. /// <param name="source"></param>
  546. /// <returns></returns>
  547. public static TSource MaxOrDefault<TSource>(this IQueryable<TSource> source) => source.DefaultIfEmpty().Max();
  548. /// <summary>
  549. /// 取最大值
  550. /// </summary>
  551. /// <typeparam name="TSource"></typeparam>
  552. /// <param name="source"></param>
  553. /// <param name="defaultValue"></param>
  554. /// <returns></returns>
  555. public static TSource MaxOrDefault<TSource>(this IQueryable<TSource> source, TSource defaultValue) => source.DefaultIfEmpty(defaultValue).Max();
  556. /// <summary>
  557. /// 取最大值
  558. /// </summary>
  559. /// <typeparam name="TSource"></typeparam>
  560. /// <typeparam name="TResult"></typeparam>
  561. /// <param name="source"></param>
  562. /// <param name="selector"></param>
  563. /// <param name="defaultValue"></param>
  564. /// <returns></returns>
  565. public static TResult MaxOrDefault<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector, TResult defaultValue) => source.Select(selector).DefaultIfEmpty(defaultValue).Max();
  566. /// <summary>
  567. /// 取最大值
  568. /// </summary>
  569. /// <typeparam name="TSource"></typeparam>
  570. /// <typeparam name="TResult"></typeparam>
  571. /// <param name="source"></param>
  572. /// <param name="selector"></param>
  573. /// <returns></returns>
  574. public static TResult MaxOrDefault<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) => source.Select(selector).DefaultIfEmpty().Max();
  575. /// <summary>
  576. /// 取最大值
  577. /// </summary>
  578. /// <typeparam name="TSource"></typeparam>
  579. /// <param name="source"></param>
  580. /// <returns></returns>
  581. public static TSource MaxOrDefault<TSource>(this IEnumerable<TSource> source) => source.DefaultIfEmpty().Max();
  582. /// <summary>
  583. /// 取最大值
  584. /// </summary>
  585. /// <typeparam name="TSource"></typeparam>
  586. /// <param name="source"></param>
  587. /// <param name="defaultValue"></param>
  588. /// <returns></returns>
  589. public static TSource MaxOrDefault<TSource>(this IEnumerable<TSource> source, TSource defaultValue) => source.DefaultIfEmpty(defaultValue).Max();
  590. /// <summary>
  591. /// 取最小值
  592. /// </summary>
  593. /// <typeparam name="TSource"></typeparam>
  594. /// <typeparam name="TResult"></typeparam>
  595. /// <param name="source"></param>
  596. /// <param name="selector"></param>
  597. /// <returns></returns>
  598. public static TResult MinOrDefault<TSource, TResult>(this IQueryable<TSource> source, Expression<Func<TSource, TResult>> selector) => source.Select(selector).DefaultIfEmpty().Min();
  599. /// <summary>
  600. /// 取最小值
  601. /// </summary>
  602. /// <typeparam name="TSource"></typeparam>
  603. /// <typeparam name="TResult"></typeparam>
  604. /// <param name="source"></param>
  605. /// <param name="selector"></param>
  606. /// <param name="defaultValue"></param>
  607. /// <returns></returns>
  608. public static TResult MinOrDefault<TSource, TResult>(this IQueryable<TSource> source, Expression<Func<TSource, TResult>> selector, TResult defaultValue) => source.Select(selector).DefaultIfEmpty(defaultValue).Min();
  609. /// <summary>
  610. /// 取最小值
  611. /// </summary>
  612. /// <typeparam name="TSource"></typeparam>
  613. /// <param name="source"></param>
  614. /// <returns></returns>
  615. public static TSource MinOrDefault<TSource>(this IQueryable<TSource> source) => source.DefaultIfEmpty().Min();
  616. /// <summary>
  617. /// 取最小值
  618. /// </summary>
  619. /// <typeparam name="TSource"></typeparam>
  620. /// <param name="source"></param>
  621. /// <param name="defaultValue"></param>
  622. /// <returns></returns>
  623. public static TSource MinOrDefault<TSource>(this IQueryable<TSource> source, TSource defaultValue) => source.DefaultIfEmpty(defaultValue).Min();
  624. /// <summary>
  625. /// 取最小值
  626. /// </summary>
  627. /// <typeparam name="TSource"></typeparam>
  628. /// <typeparam name="TResult"></typeparam>
  629. /// <param name="source"></param>
  630. /// <param name="selector"></param>
  631. /// <returns></returns>
  632. public static TResult MinOrDefault<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) => source.Select(selector).DefaultIfEmpty().Min();
  633. /// <summary>
  634. /// 取最小值
  635. /// </summary>
  636. /// <typeparam name="TSource"></typeparam>
  637. /// <typeparam name="TResult"></typeparam>
  638. /// <param name="source"></param>
  639. /// <param name="selector"></param>
  640. /// <param name="defaultValue"></param>
  641. /// <returns></returns>
  642. public static TResult MinOrDefault<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector, TResult defaultValue) => source.Select(selector).DefaultIfEmpty(defaultValue).Min();
  643. /// <summary>
  644. /// 取最小值
  645. /// </summary>
  646. /// <typeparam name="TSource"></typeparam>
  647. /// <param name="source"></param>
  648. /// <returns></returns>
  649. public static TSource MinOrDefault<TSource>(this IEnumerable<TSource> source) => source.DefaultIfEmpty().Min();
  650. /// <summary>
  651. /// 取最小值
  652. /// </summary>
  653. /// <typeparam name="TSource"></typeparam>
  654. /// <param name="source"></param>
  655. /// <param name="defaultValue"></param>
  656. /// <returns></returns>
  657. public static TSource MinOrDefault<TSource>(this IEnumerable<TSource> source, TSource defaultValue) => source.DefaultIfEmpty(defaultValue).Min();
  658. /// <summary>
  659. /// 标准差
  660. /// </summary>
  661. /// <typeparam name="T"></typeparam>
  662. /// <param name="source"></param>
  663. /// <param name="selector"></param>
  664. /// <returns></returns>
  665. public static TResult StandardDeviation<T, TResult>(this IEnumerable<T> source, Func<T, TResult> selector) where TResult : IConvertible
  666. {
  667. return StandardDeviation(source.Select(t => selector(t).ConvertTo<double>())).ConvertTo<TResult>();
  668. }
  669. /// <summary>
  670. /// 标准差
  671. /// </summary>
  672. /// <typeparam name="T"></typeparam>
  673. /// <param name="source"></param>
  674. /// <returns></returns>
  675. public static T StandardDeviation<T>(this IEnumerable<T> source) where T : IConvertible
  676. {
  677. return StandardDeviation(source.Select(t => t.ConvertTo<double>())).ConvertTo<T>();
  678. }
  679. /// <summary>
  680. /// 标准差
  681. /// </summary>
  682. /// <param name="source"></param>
  683. /// <returns></returns>
  684. public static double StandardDeviation(this IEnumerable<double> source)
  685. {
  686. double result = 0;
  687. int count = source.Count();
  688. if (count > 1)
  689. {
  690. double avg = source.Average();
  691. double sum = source.Sum(d => (d - avg) * (d - avg));
  692. result = Math.Sqrt(sum / count);
  693. }
  694. return result;
  695. }
  696. /// <summary>
  697. /// 随机排序
  698. /// </summary>
  699. /// <typeparam name="T"></typeparam>
  700. /// <param name="source"></param>
  701. /// <returns></returns>
  702. public static IOrderedEnumerable<T> OrderByRandom<T>(this IEnumerable<T> source)
  703. {
  704. return source.OrderBy(_ => Guid.NewGuid());
  705. }
  706. /// <summary>
  707. /// 序列相等
  708. /// </summary>
  709. /// <typeparam name="T"></typeparam>
  710. /// <param name="first"></param>
  711. /// <param name="second"></param>
  712. /// <param name="condition"></param>
  713. /// <returns></returns>
  714. public static bool SequenceEqual<T>(this IEnumerable<T> first, IEnumerable<T> second, Func<T, T, bool> condition)
  715. {
  716. if (first is ICollection<T> source1 && second is ICollection<T> source2)
  717. {
  718. if (source1.Count != source2.Count)
  719. {
  720. return false;
  721. }
  722. if (source1 is IList<T> list1 && source2 is IList<T> list2)
  723. {
  724. int count = source1.Count;
  725. for (int index = 0; index < count; ++index)
  726. {
  727. if (!condition(list1[index], list2[index]))
  728. {
  729. return false;
  730. }
  731. }
  732. return true;
  733. }
  734. }
  735. using IEnumerator<T> enumerator1 = first.GetEnumerator();
  736. using IEnumerator<T> enumerator2 = second.GetEnumerator();
  737. while (enumerator1.MoveNext())
  738. {
  739. if (!enumerator2.MoveNext() || !condition(enumerator1.Current, enumerator2.Current))
  740. {
  741. return false;
  742. }
  743. }
  744. return !enumerator2.MoveNext();
  745. }
  746. /// <summary>
  747. /// 序列相等
  748. /// </summary>
  749. /// <typeparam name="T1"></typeparam>
  750. /// <typeparam name="T2"></typeparam>
  751. /// <param name="first"></param>
  752. /// <param name="second"></param>
  753. /// <param name="condition"></param>
  754. /// <returns></returns>
  755. public static bool SequenceEqual<T1, T2>(this IEnumerable<T1> first, IEnumerable<T2> second, Func<T1, T2, bool> condition)
  756. {
  757. if (first is ICollection<T1> source1 && second is ICollection<T2> source2)
  758. {
  759. if (source1.Count != source2.Count)
  760. {
  761. return false;
  762. }
  763. if (source1 is IList<T1> list1 && source2 is IList<T2> list2)
  764. {
  765. int count = source1.Count;
  766. for (int index = 0; index < count; ++index)
  767. {
  768. if (!condition(list1[index], list2[index]))
  769. {
  770. return false;
  771. }
  772. }
  773. return true;
  774. }
  775. }
  776. using IEnumerator<T1> enumerator1 = first.GetEnumerator();
  777. using IEnumerator<T2> enumerator2 = second.GetEnumerator();
  778. while (enumerator1.MoveNext())
  779. {
  780. if (!enumerator2.MoveNext() || !condition(enumerator1.Current, enumerator2.Current))
  781. {
  782. return false;
  783. }
  784. }
  785. return !enumerator2.MoveNext();
  786. }
  787. /// <summary>
  788. /// 对比两个集合哪些是新增的、删除的、修改的
  789. /// </summary>
  790. /// <typeparam name="T1"></typeparam>
  791. /// <typeparam name="T2"></typeparam>
  792. /// <param name="first"></param>
  793. /// <param name="second"></param>
  794. /// <param name="condition">对比因素条件</param>
  795. /// <returns></returns>
  796. public static (List<T1> adds, List<T2> remove, List<T1> updates) CompareChanges<T1, T2>(this IEnumerable<T1> first, IEnumerable<T2> second, Func<T1, T2, bool> condition)
  797. {
  798. var add = first.ExceptBy(second, condition).ToList();
  799. var remove = second.ExceptBy(first, (s, f) => condition(f, s)).ToList();
  800. var update = first.IntersectBy(second, condition).ToList();
  801. return (add, remove, update);
  802. }
  803. /// <summary>
  804. /// 对比两个集合哪些是新增的、删除的、修改的
  805. /// </summary>
  806. /// <typeparam name="T1"></typeparam>
  807. /// <typeparam name="T2"></typeparam>
  808. /// <param name="first"></param>
  809. /// <param name="second"></param>
  810. /// <param name="condition">对比因素条件</param>
  811. /// <returns></returns>
  812. public static (List<T1> adds, List<T2> remove, List<(T1 first, T2 second)> updates) CompareChangesPlus<T1, T2>(this IEnumerable<T1> first, IEnumerable<T2> second, Func<T1, T2, bool> condition)
  813. {
  814. var add = first.ExceptBy(second, condition).ToList();
  815. var remove = second.ExceptBy(first, (s, f) => condition(f, s)).ToList();
  816. var updates = first.IntersectBy(second, condition).Select(t1 => (t1, second.FirstOrDefault(t2 => condition(t1, t2)))).ToList();
  817. return (add, remove, updates);
  818. }
  819. public static List<T> AsNotNull<T>(this List<T> list)
  820. {
  821. return list ?? new List<T>();
  822. }
  823. public static IEnumerable<T> AsNotNull<T>(this IEnumerable<T> list)
  824. {
  825. return list ?? new List<T>();
  826. }
  827. public static IEnumerable<T> WhereIf<T>(this IEnumerable<T> source, bool condition, Func<T, bool> where)
  828. {
  829. return condition ? source.Where(where) : source;
  830. }
  831. public static IEnumerable<T> WhereIf<T>(this IEnumerable<T> source, Func<bool> condition, Func<T, bool> where)
  832. {
  833. return condition() ? source.Where(where) : source;
  834. }
  835. public static IQueryable<T> WhereIf<T>(this IQueryable<T> source, bool condition, Expression<Func<T, bool>> where)
  836. {
  837. return condition ? source.Where(where) : source;
  838. }
  839. public static IQueryable<T> WhereIf<T>(this IQueryable<T> source, Func<bool> condition, Expression<Func<T, bool>> where)
  840. {
  841. return condition() ? source.Where(where) : source;
  842. }
  843. }
  844. }