Entension methods for finding indices in a sequence, and finding the closest item in a sequence

ICD.Common.Utils.Tests/Extensions/EnumerableExtensionsTest.cs

@@ -37,7 +37,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 			Assert.AreEqual(0, result);
 			Assert.AreEqual(false, exists);
 
-            sequence = new[] { expected };
+			sequence = new[] {expected};
 			exists = sequence.TryFirst(out result);
 
 			Assert.AreEqual(expected, result);
@@ -55,7 +55,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 			Assert.AreEqual(0, result);
 			Assert.AreEqual(false, exists);
 
-            sequence = new[] { expected };
+			sequence = new[] {expected};
 			exists = sequence.TryFirst(i => i == expected, out result);
 
 			Assert.AreEqual(expected, result);
@@ -73,7 +73,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 			Assert.AreEqual(0, result);
 			Assert.AreEqual(false, exists);
 
-            sequence = new[] { expected };
+			sequence = new[] {expected};
 			exists = sequence.TryElementAt(0, out result);
 
 			Assert.AreEqual(expected, result);
@@ -83,8 +83,8 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void SequenceEqualTest()
 		{
-            int[] a = new[] { 1, 2, 3, 4};
+			int[] a = new[] {1, 2, 3, 4};
-            int[] b = new[] { 1, 4, 9, 16};
+			int[] b = new[] {1, 4, 9, 16};
 
 			Assert.IsFalse(a.SequenceEqual(b, (x, y) => x == y));
 			Assert.IsTrue(a.SequenceEqual(b, (x, y) => x * x == y));
@@ -93,10 +93,10 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ScrambledEqualsTest()
 		{
-            IEnumerable<int> a = new[] { 1, 2, 3, 4 };
+			IEnumerable<int> a = new[] {1, 2, 3, 4};
-            IEnumerable<int> b = new[] { 3, 1, 2, 4 };
+			IEnumerable<int> b = new[] {3, 1, 2, 4};
-            IEnumerable<int> c = new[] { 1, 2, 3, 4, 4 };
+			IEnumerable<int> c = new[] {1, 2, 3, 4, 4};
-            IEnumerable<int> d = new[] { 1, 2, 3, 4, 5 };
+			IEnumerable<int> d = new[] {1, 2, 3, 4, 5};
 
 			Assert.IsTrue(a.ScrambledEquals(b));
 			Assert.IsFalse(a.ScrambledEquals(c));
@@ -106,10 +106,10 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ScrambledEqualsComparerTest()
 		{
-            IEnumerable<int> a = new[] { 1, 2, 3, 4 };
+			IEnumerable<int> a = new[] {1, 2, 3, 4};
-            IEnumerable<int> b = new[] { 3, 1, 2, 4 };
+			IEnumerable<int> b = new[] {3, 1, 2, 4};
-            IEnumerable<int> c = new[] { 1, 2, 3, 4, 4 };
+			IEnumerable<int> c = new[] {1, 2, 3, 4, 4};
-            IEnumerable<int> d = new[] { 1, 2, 3, 4, 5 };
+			IEnumerable<int> d = new[] {1, 2, 3, 4, 5};
 
 			Assert.IsTrue(a.ScrambledEquals(b, EqualityComparer<int>.Default));
 			Assert.IsFalse(a.ScrambledEquals(c, EqualityComparer<int>.Default));
@@ -119,14 +119,26 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void FindIndexPredicateTest()
 		{
-            IEnumerable<int> a = new[] { 1, 2, 3, 4 };
+			IEnumerable<int> a = new[] {1, 2, 3, 4};
 			Assert.AreEqual(2, a.FindIndex(i => i == 3));
 		}
 
+		[Test]
+		public void FindIndicesPredicateTest()
+		{
+			IEnumerable<int> a = new[] {1, 2, 3, 4};
+
+			int[] indices = a.FindIndices(i => i % 2 == 0).ToArray();
+
+			Assert.AreEqual(2, indices.Length);
+			Assert.AreEqual(1, indices[0]);
+			Assert.AreEqual(3, indices[1]);
+		}
+
 		[Test]
 		public void SelectMultiTest()
 		{
-            int[] values = { 1, 2, 3 };
+			int[] values = {1, 2, 3};
 			int[] result = values.SelectMulti(i => 1, i => 2).ToArray();
 
 			Assert.AreEqual(6, result.Length);
@@ -141,10 +153,14 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ExecuteTest()
 		{
-            int[] values = { 1, 2, 3 };
+			int[] values = {1, 2, 3};
 
 			int sum = 0;
-            IEnumerable<int> sequence = values.Select(v => { sum += v; return v; });
+			IEnumerable<int> sequence = values.Select(v =>
+			                                          {
+				                                          sum += v;
+				                                          return v;
+			                                          });
 
 			Assert.AreEqual(0, sum);
 			sequence.Execute();
@@ -154,7 +170,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ForEachTest()
 		{
-            int[] values = { 1, 2, 3 };
+			int[] values = {1, 2, 3};
 
 			int sum = 0;
 			values.ForEach(v => sum += v);
@@ -165,7 +181,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ForEachIndexTest()
 		{
-            int[] values = { 1, 2, 3 };
+			int[] values = {1, 2, 3};
 
 			int sum = 0;
 			values.ForEach((v, i) => sum += i);
@@ -184,7 +200,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void PrependManyTest()
 		{
-            int[] values = (new[] { 4, 5, 6 }).PrependMany(1, 2, 3).ToArray();
+			int[] values = (new[] {4, 5, 6}).PrependMany(1, 2, 3).ToArray();
 
 			Assert.AreEqual(6, values.Length);
 			Assert.AreEqual(1, values[0]);
@@ -206,7 +222,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void AppendManyTest()
 		{
-            int[] values = (new[] { 1, 2, 3 }).AppendMany(4, 5, 6).ToArray();
+			int[] values = (new[] {1, 2, 3}).AppendMany(4, 5, 6).ToArray();
 
 			Assert.AreEqual(6, values.Length);
 			Assert.AreEqual(1, values[0]);
@@ -220,7 +236,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void OrderTest()
 		{
-            int[] values = (new[] { 2, 3, 1 }).Order().ToArray();
+			int[] values = (new[] {2, 3, 1}).Order().ToArray();
 
 			Assert.AreEqual(3, values.Length);
 			Assert.AreEqual(1, values[0]);
@@ -231,7 +247,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ExceptTest()
 		{
-            int[] values = (new[] { 1, 2, 3 }).Except(2).ToArray();
+			int[] values = (new[] {1, 2, 3}).Except(2).ToArray();
 
 			Assert.AreEqual(2, values.Length);
 			Assert.AreEqual(1, values[0]);
@@ -241,7 +257,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ToHashSetTest()
 		{
-            IcdHashSet<int> values = (new[] { 1, 2, 3 }).ToHashSet();
+			IcdHashSet<int> values = (new[] {1, 2, 3}).ToHashSet();
 
 			Assert.AreEqual(3, values.Count);
 			Assert.IsTrue(values.Contains(1));
@@ -252,7 +268,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ToDictionaryIntTest()
 		{
-            Dictionary<int, int> values = (new[] { 1, 2, 3 }).ToDictionary();
+			Dictionary<int, int> values = (new[] {1, 2, 3}).ToDictionary();
 
 			Assert.AreEqual(3, values.Count);
 			Assert.AreEqual(1, values[0]);
@@ -263,7 +279,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ToDictionaryUIntTest()
 		{
-            Dictionary<uint, int> values = (new[] { 1, 2, 3 }).ToDictionaryUInt();
+			Dictionary<uint, int> values = (new[] {1, 2, 3}).ToDictionaryUInt();
 
 			Assert.AreEqual(3, values.Count);
 			Assert.AreEqual(1, values[0]);
@@ -292,24 +308,24 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void UnanimousTest()
 		{
-            Assert.IsTrue((new[] { true, true, true}).Unanimous());
+			Assert.IsTrue((new[] {true, true, true}).Unanimous());
-            Assert.IsTrue((new[] { false, false, false }).Unanimous());
+			Assert.IsTrue((new[] {false, false, false}).Unanimous());
-            Assert.IsFalse((new[] { false, true, false }).Unanimous());
+			Assert.IsFalse((new[] {false, true, false}).Unanimous());
 			Assert.IsFalse((new bool[] { }).Unanimous());
 		}
 
 		[Test]
 		public void UnanimousOtherTest()
 		{
-            Assert.AreEqual("A", (new[] { "A", "A", "A" }).Unanimous("B"));
+			Assert.AreEqual("A", (new[] {"A", "A", "A"}).Unanimous("B"));
-            Assert.AreEqual("C", (new[] { "B", "A", "B" }).Unanimous("C"));
+			Assert.AreEqual("C", (new[] {"B", "A", "B"}).Unanimous("C"));
 			Assert.AreEqual("A", (new string[] { }).Unanimous("A"));
 		}
 
 		[Test]
 		public void PartitionTest()
 		{
-            int[][] items = (new[] { 1, 2, 3, 4, 5, 6, 7, 8 }).Partition(3)
+			int[][] items = (new[] {1, 2, 3, 4, 5, 6, 7, 8}).Partition(3)
 			                                                .Select(p => p.ToArray())
 			                                                .ToArray();
 
@@ -334,13 +350,13 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void GetAdjacentPairsTest()
 		{
-            IEnumerable<int> a = new int[] {};
+			IEnumerable<int> a = new int[] { };
 			Assert.AreEqual(0, a.GetAdjacentPairs().Count());
 
-            IEnumerable<int> b = new[] { 1 };
+			IEnumerable<int> b = new[] {1};
 			Assert.AreEqual(0, b.GetAdjacentPairs().Count());
 
-            IEnumerable<int> c = new[] { 1, 2, 3 };
+			IEnumerable<int> c = new[] {1, 2, 3};
 			int[][] cPairs = c.GetAdjacentPairs().ToArray();
 
 			Assert.AreEqual(2, cPairs.Length);
@@ -350,17 +366,23 @@ namespace ICD.Common.Utils.Tests.Extensions
 			Assert.AreEqual(3, cPairs[1][1]);
 		}
 
+		[Test]
+		public void GetClosestTest()
+		{
+			Assert.AreEqual(20, new[] {10, 15, 20, 30, 35}.GetClosest(i => i - 21));
+		}
+
 		[Test]
 		public void MinByTest()
 		{
-            Assert.AreEqual(1, new[] { 3, 6, 2, 7, 1 }.MinBy(i => i));
+			Assert.AreEqual(1, new[] {3, 6, 2, 7, 1}.MinBy(i => i));
 		}
 
 		[Test]
 		public void MinByComparerTest()
 		{
 			IComparer<int> comparer = new NegativeComparer();
-            Assert.AreEqual(7, new[] { 3, 6, 2, 7, 1 }.MinBy(i => i, comparer));
+			Assert.AreEqual(7, new[] {3, 6, 2, 7, 1}.MinBy(i => i, comparer));
 		}
 
 		private class NegativeComparer : IComparer<int>
@@ -374,7 +396,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ExceptNullsTest()
 		{
-            IEnumerable<int?> sequence = new int?[] { 1, 2, null, 3, 4, null };
+			IEnumerable<int?> sequence = new int?[] {1, 2, null, 3, 4, null};
 			int[] result = sequence.ExceptNulls().ToArray();
 
 			Assert.AreEqual(4, result.Length);
@@ -387,14 +409,14 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void SumTest()
 		{
-            IEnumerable<byte> sequence = new byte[] { 1, 2, 3, 4 };
+			IEnumerable<byte> sequence = new byte[] {1, 2, 3, 4};
 			Assert.AreEqual(10, sequence.Sum());
 		}
 
 		[Test]
 		public void ConsolidateTest()
 		{
-            string[] sequence = EnumerableExtensions.Consolidate(new[] { "A", "B", "B", "C" }).ToArray();
+			string[] sequence = EnumerableExtensions.Consolidate(new[] {"A", "B", "B", "C"}).ToArray();
 
 			Assert.AreEqual(3, sequence.Length, StringUtils.ArrayFormat(sequence));
 			Assert.AreEqual("A", sequence[0]);
@@ -405,7 +427,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void ConsolidateComparerTest()
 		{
-            string[] sequence = EnumerableExtensions.Consolidate(new[] { "A", "B", "B", "C" }, Comparer<string>.Default).ToArray();
+			string[] sequence = EnumerableExtensions.Consolidate(new[] {"A", "B", "B", "C"}, Comparer<string>.Default).ToArray();
 
 			Assert.AreEqual(3, sequence.Length, StringUtils.ArrayFormat(sequence));
 			Assert.AreEqual("A", sequence[0]);
@@ -416,7 +438,7 @@ namespace ICD.Common.Utils.Tests.Extensions
 		[Test]
 		public void AnyAndAllTest()
 		{
-            IEnumerable<int> sequence = new[] { 1, 2, 3, 4 };
+			IEnumerable<int> sequence = new[] {1, 2, 3, 4};
 
 			Assert.IsTrue(sequence.AnyAndAll(i => i > 0));
 			Assert.IsFalse(sequence.AnyAndAll(i => i < 0));

ICD.Common.Utils/Extensions/EnumerableExtensions.cs

@@ -226,6 +226,24 @@ namespace ICD.Common.Utils.Extensions
 		/// <param name="match"></param>
 		/// <returns></returns>
 		public static int FindIndex<T>(this IEnumerable<T> extends, Predicate<T> match)
+		{
+			if (extends == null)
+				throw new ArgumentNullException("extends");
+
+			if (match == null)
+				throw new ArgumentNullException("match");
+
+			return extends.FindIndices(match).FirstOrDefault(-1);
+		}
+
+		/// <summary>
+		/// Returns the indices that match the predicate.
+		/// </summary>
+		/// <typeparam name="T"></typeparam>
+		/// <param name="extends"></param>
+		/// <param name="match"></param>
+		/// <returns></returns>
+		public static IEnumerable<int> FindIndices<T>(this IEnumerable<T> extends, Predicate<T> match)
 		{
 			if (extends == null)
 				throw new ArgumentNullException("extends");
@@ -238,11 +256,9 @@ namespace ICD.Common.Utils.Extensions
 			foreach (T item in extends)
 			{
 				if (match(item))
-					return index;
+					yield return index;
 				index++;
 			}
-
-			return -1;
 		}
 
 		/// <summary>
@@ -583,6 +599,18 @@ namespace ICD.Common.Utils.Extensions
 			}
 		}
 
+		/// <summary>
+		/// Gets the item from the sequence with the smallest calculated delta.
+		/// </summary>
+		/// <typeparam name="T"></typeparam>
+		/// <param name="extends"></param>
+		/// <param name="getDelta"></param>
+		/// <returns></returns>
+		public static T GetClosest<T>(this IEnumerable<T> extends, Func<T, int> getDelta)
+		{
+			return extends.MinBy(n => Math.Abs(getDelta(n)));
+		}
+
 		/// <summary>
 		/// Returns the minimal element of the given sequence, based on
 		/// the given projection.