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Add DataTable and Enumerable helpers
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3 files changed

+253
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‎SharpHelpers/SharpHelpers.UnitTest/SharpHelpers.UnitTest.csproj‎

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@@ -8,8 +8,8 @@
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<ItemGroup>
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<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
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<PackageReference Include="MSTest.TestAdapter" Version="3.6.1" />
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<PackageReference Include="MSTest.TestFramework" Version="3.6.1" />
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<PackageReference Include="MSTest.TestAdapter" Version="3.6.2" />
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<PackageReference Include="MSTest.TestFramework" Version="3.6.2" />
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</ItemGroup>
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<ItemGroup>

‎SharpHelpers/SharpHelpers/DataTableHelper.cs‎

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@@ -3,6 +3,7 @@
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using System;
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using System.Collections.Generic;
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using System.Data;
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using System.Linq;
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using System.Reflection;
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namespace SharpCoding.SharpHelpers
@@ -51,6 +52,139 @@ public static DataTable SetColumnsOrder(this DataTable table, string[] columnNam
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list.Add(objClass);
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}
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return list;
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}
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/// <summary>
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/// Converts the DataTable to a CSV format string.
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/// </summary>
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/// <param name="table"></param>
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/// <param name="delimiter"></param>
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/// <returns></returns>
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public static string ToCsv(this DataTable table, string delimiter = ",")
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{
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if (table == null) throw new ArgumentNullException(nameof(table));
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var csv = new List<string>();
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var headers = string.Join(delimiter, table.Columns.Cast<DataColumn>().Select(c => c.ColumnName));
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csv.Add(headers);
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foreach (DataRow row in table.Rows)
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{
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var line = string.Join(delimiter, row.ItemArray.Select(field => field?.ToString()));
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csv.Add(line);
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}
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return string.Join(Environment.NewLine, csv);
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}
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/// <summary>
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/// Adds a new column to the DataTable with the specified default value.
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/// </summary>
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/// <param name="table"></param>
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/// <param name="columnName"></param>
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/// <param name="defaultValue"></param>
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/// <typeparam name="T"></typeparam>
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public static void AddColumn<T>(this DataTable table, string columnName, T defaultValue = default)
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{
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if (table == null) throw new ArgumentNullException(nameof(table));
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var column = new DataColumn(columnName, typeof(T)) { DefaultValue = defaultValue };
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table.Columns.Add(column);
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foreach (DataRow row in table.Rows)
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{
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row[columnName] = defaultValue;
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}
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}
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/// <summary>
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/// Merges multiple DataTables with the same schema into one.
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/// </summary>
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/// <param name="tables"></param>
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/// <returns></returns>
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/// <exception cref="ArgumentException"></exception>
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public static DataTable MergeTables(IEnumerable<DataTable> tables)
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{
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if (tables == null) throw new ArgumentNullException(nameof(tables));
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var resultTable = tables.First().Clone();
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foreach (var table in tables)
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{
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if (!AreSchemasCompatible(resultTable, table))
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throw new ArgumentException("Tables have incompatible schemas.");
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foreach (DataRow row in table.Rows)
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{
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resultTable.ImportRow(row);
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}
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}
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return resultTable;
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}
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private static bool AreSchemasCompatible(DataTable table1, DataTable table2)
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{
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if (table1.Columns.Count != table2.Columns.Count) return false;
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for (int i = 0; i < table1.Columns.Count; i++)
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{
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if (table1.Columns[i].ColumnName != table2.Columns[i].ColumnName ||
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table1.Columns[i].DataType != table2.Columns[i].DataType)
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return false;
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}
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return true;
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}
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/// <summary>
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/// Filters the rows in the DataTable based on a predicate.
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/// </summary>
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/// <param name="table"></param>
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/// <param name="predicate"></param>
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/// <returns></returns>
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public static DataTable Filter(this DataTable table, Func<DataRow, bool> predicate)
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{
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if (table == null) throw new ArgumentNullException(nameof(table));
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if (predicate == null) throw new ArgumentNullException(nameof(predicate));
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var filteredTable = table.Clone();
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foreach (DataRow row in table.AsEnumerable().Where(predicate))
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{
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filteredTable.ImportRow(row);
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}
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return filteredTable;
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}
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/// <summary>
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/// Checks if the DataTable is empty (contains no rows).
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/// </summary>
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/// <param name="table"></param>
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/// <returns></returns>
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public static bool IsEmpty(this DataTable table)
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{
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if (table == null) throw new ArgumentNullException(nameof(table));
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return table.Rows.Count == 0;
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}
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/// <summary>
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/// Removes duplicate rows based on specified columns.
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/// </summary>
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/// <param name="table"></param>
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/// <param name="columnNames"></param>
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/// <returns></returns>
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public static DataTable RemoveDuplicates(this DataTable table, params string[] columnNames)
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{
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if (table == null) throw new ArgumentNullException(nameof(table));
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var distinctTable = table.Clone();
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var uniqueRows = new HashSet<string>();
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foreach (DataRow row in table.Rows)
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{
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var key = string.Join("|", columnNames.Select(c => row[c]?.ToString() ?? ""));
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if (uniqueRows.Add(key))
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{
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distinctTable.ImportRow(row);
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}
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}
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return distinctTable;
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}
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}
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}

‎SharpHelpers/SharpHelpers/EnumerableHelper.cs‎

Lines changed: 117 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -268,5 +268,122 @@ public static int Sum<T>(this IEnumerable<T> source, Func<T, int> selector)
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return source.Select(selector).Sum();
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}
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/// <summary>
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/// Returns the maximum element based on a given selector function.
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/// </summary>
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/// <typeparam name="TSource"></typeparam>
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/// <typeparam name="TKey"></typeparam>
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/// <param name="source"></param>
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/// <param name="selector"></param>
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/// <returns></returns>
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/// <exception cref="ArgumentNullException"></exception>
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public static TSource MaxBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> selector)
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where TKey : IComparable<TKey>
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{
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if (source == null) throw new ArgumentNullException(nameof(source));
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if (selector == null) throw new ArgumentNullException(nameof(selector));
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return source.Aggregate((maxItem, nextItem) => selector(nextItem).CompareTo(selector(maxItem)) > 0 ? nextItem : maxItem);
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}
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/// <summary>
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/// Returns the minimum element based on a given selector function.
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/// </summary>
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/// <typeparam name="TSource"></typeparam>
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/// <typeparam name="TKey"></typeparam>
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/// <param name="source"></param>
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/// <param name="selector"></param>
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/// <returns></returns>
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/// <exception cref="ArgumentNullException"></exception>
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public static TSource MinBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> selector)
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where TKey : IComparable<TKey>
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{
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if (source == null) throw new ArgumentNullException(nameof(source));
303+
if (selector == null) throw new ArgumentNullException(nameof(selector));
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return source.Aggregate((minItem, nextItem) => selector(nextItem).CompareTo(selector(minItem)) < 0 ? nextItem : minItem);
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}
307+
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/// <summary>
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/// Finds the index of the first element that satisfies a given predicate.
310+
/// </summary>
311+
/// <typeparam name="T"></typeparam>
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/// <param name="source"></param>
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/// <param name="predicate"></param>
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/// <returns></returns>
315+
/// <exception cref="ArgumentNullException"></exception>
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public static int FindIndex<T>(this IEnumerable<T> source, Func<T, bool> predicate)
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{
318+
if (source == null) throw new ArgumentNullException(nameof(source));
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if (predicate == null) throw new ArgumentNullException(nameof(predicate));
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int index = 0;
322+
foreach (var item in source)
323+
{
324+
if (predicate(item)) return index;
325+
index++;
326+
}
327+
return -1;
328+
}
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/// <summary>
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/// Checks if the source contains any of the specified items.
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/// </summary>
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/// <typeparam name="T"></typeparam>
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/// <param name="source"></param>
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/// <param name="items"></param>
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/// <returns></returns>
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/// <exception cref="ArgumentNullException"></exception>
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public static bool ContainsAny<T>(this IEnumerable<T> source, params T[] items)
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{
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if (source == null) throw new ArgumentNullException(nameof(source));
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if (items == null) throw new ArgumentNullException(nameof(items));
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var set = new HashSet<T>(items);
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return source.Any(set.Contains);
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}
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/// <summary>
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/// Checks if the source contains all of the specified items.
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/// </summary>
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/// <typeparam name="T"></typeparam>
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/// <param name="source"></param>
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/// <param name="items"></param>
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/// <returns></returns>
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/// <exception cref="ArgumentNullException"></exception>
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public static bool ContainsAll<T>(this IEnumerable<T> source, params T[] items)
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{
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if (source == null) throw new ArgumentNullException(nameof(source));
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if (items == null) throw new ArgumentNullException(nameof(items));
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var set = new HashSet<T>(source);
361+
return items.All(set.Contains);
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}
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/// <summary>
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/// Returns the median of a sequence of numbers.
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/// </summary>
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/// <param name="source"></param>
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/// <returns></returns>
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/// <exception cref="ArgumentNullException"></exception>
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public static double Median(this IEnumerable<int> source)
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{
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if (source == null) throw new ArgumentNullException(nameof(source));
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var sortedList = source.OrderBy(n => n).ToList();
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int count = sortedList.Count;
376+
if (count == 0)
377+
throw new InvalidOperationException("The source sequence is empty.");
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if (count % 2 == 0)
380+
{
381+
return (sortedList[count / 2 - 1] + sortedList[count / 2]) / 2.0;
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}
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else
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{
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return sortedList[count / 2];
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}
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}
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}
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}

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