Add DataTable and Enumerable helpers

SharpHelpers/SharpHelpers.UnitTest/SharpHelpers.UnitTest.csproj

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

SharpHelpers/SharpHelpers/DataTableHelper.cs

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

SharpHelpers/SharpHelpers/EnumerableHelper.cs

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