Added Arrays.Insert and Arrays.AppendAt

Nucs · Nucs · commit a83a3f6d3182 · 2019-07-31T23:31:00.000+03:00
diff --git a/src/NumSharp.Core/Utilities/Arrays.cs b/src/NumSharp.Core/Utilities/Arrays.cs
@@ -12,6 +12,34 @@ namespace NumSharp.Utilities
 {
     public static class Arrays
     {
+        /// <summary>
+        ///     Inserts item into a specific index.
+        /// </summary>
+        /// <param name="source">The array to insert the value to.</param>
+        /// <param name="index">The index to insert to.</param>
+        /// <returns></returns>
+        public static void Insert<T>(ref T[] source, int index, T value)
+        {
+            if (index < 0 || index >= source.Length)
+                throw new ArgumentOutOfRangeException(nameof(index));
+
+            Array.Resize(ref source, source.Length + 1);
+            Array.Copy(source, index, source, index + 1, source.Length-index - 1);
+            source[index] = value;
+        }
+
+        /// <summary>
+        ///     Inserts item into a specific index.
+        /// </summary>
+        /// <param name="source">The array to insert copy and insert value to.</param>
+        /// <param name="index">The index to insert to.</param>
+        /// <returns>a copy of <see cref="source"/> with the appended value.</returns>
+        public static T[] AppendAt<T>(T[] source, int index, T value)
+        {
+            var ret = (T[])source.Clone();
+            Insert(ref source, index, value);
+            return ret;
+        }
         /// <summary>
         ///     Removes a specific index from given array.
         /// </summary>
diff --git a/test/NumSharp.UnitTest/Utilities/ArraysTests.cs b/test/NumSharp.UnitTest/Utilities/ArraysTests.cs
@@ -35,5 +35,51 @@ public void Create_4()
         {
             Arrays.Create(NPTypeCode.NDArray, 1000).Should().BeOfType<NDArray[]>().And.HaveCount(1000);
         }
+
+        [TestMethod]
+        public void Insert_0()
+        {
+            int index = 0;
+            var a = Enumerable.Range(0, 10).ToArray();
+            Arrays.Insert(ref a, index, 9);
+            a[index].Should().Be(9);
+            var l = a.ToList();
+            l.RemoveAt(index);
+            Enumerable.SequenceEqual(l, Enumerable.Range(0, 10)).Should().BeTrue();
+        }
+        [TestMethod]
+        public void Insert_2()
+        {
+            int index = 2;
+            var a = Enumerable.Range(0, 10).ToArray();
+            Arrays.Insert(ref a, index, 9);
+            a[index].Should().Be(9);
+            var l = a.ToList();
+            l.RemoveAt(index);
+            Enumerable.SequenceEqual(l, Enumerable.Range(0, 10)).Should().BeTrue();
+        }
+        [TestMethod]
+        public void Insert_5()
+        {
+            int index = 5;
+            var a = Enumerable.Range(0, 10).ToArray();
+            Arrays.Insert(ref a, index, 9);
+            a[index].Should().Be(9);
+            var l = a.ToList();
+            l.RemoveAt(index);
+            Enumerable.SequenceEqual(l, Enumerable.Range(0, 10)).Should().BeTrue();
+        }
+        [TestMethod]
+        public void Insert_9()
+        {
+            int index = 9;
+            var a = Enumerable.Range(0, 10).ToArray();
+            Arrays.Insert(ref a, index, 3);
+            a[index].Should().Be(3);
+            var l = a.ToList();
+            l.RemoveAt(index);
+            Enumerable.SequenceEqual(l, Enumerable.Range(0, 10)).Should().BeTrue();
+        }
+
     }
 }
