From 303ba62d10d25edc282ba811e2dbbc4a739f8fc4 Mon Sep 17 00:00:00 2001
From: Prashanth Govindarajan <prgovi@microsoft.com>
Date: Thu, 5 Dec 2019 16:14:18 -0800
Subject: [PATCH] Params constructor on DataFrame (#2800)

* Params constructor on DataFrame

* Delete redundant constructors
---
 src/Microsoft.Data.Analysis/DataFrame.cs              |  7 ++++---
 .../DataFrameColumnCollection.cs                      | 11 +++--------
 tests/Microsoft.Data.Analysis.Tests/DataFrameTests.cs |  6 ++++++
 3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/Microsoft.Data.Analysis/DataFrame.cs b/src/Microsoft.Data.Analysis/DataFrame.cs
index 6bf50f46c9..d6e5b1bcc6 100644
--- a/src/Microsoft.Data.Analysis/DataFrame.cs
+++ b/src/Microsoft.Data.Analysis/DataFrame.cs
@@ -33,13 +33,14 @@ public partial class DataFrame
     {
         private readonly DataFrameColumnCollection _columnCollection;
         private readonly DataFrameRowCollection _rowCollection;
-        public DataFrame()
+
+        public DataFrame(IEnumerable<DataFrameColumn> columns)
         {
-            _columnCollection = new DataFrameColumnCollection(OnColumnsChanged);
+            _columnCollection = new DataFrameColumnCollection(columns, OnColumnsChanged);
             _rowCollection = new DataFrameRowCollection(this);
         }
 
-        public DataFrame(IList<DataFrameColumn> columns)
+        public DataFrame(params DataFrameColumn[] columns)
         {
             _columnCollection = new DataFrameColumnCollection(columns, OnColumnsChanged);
             _rowCollection = new DataFrameRowCollection(this);
diff --git a/src/Microsoft.Data.Analysis/DataFrameColumnCollection.cs b/src/Microsoft.Data.Analysis/DataFrameColumnCollection.cs
index 68861f2f43..e362af2b15 100644
--- a/src/Microsoft.Data.Analysis/DataFrameColumnCollection.cs
+++ b/src/Microsoft.Data.Analysis/DataFrameColumnCollection.cs
@@ -21,18 +21,13 @@ public class DataFrameColumnCollection : Collection<DataFrameColumn>
 
         internal long RowCount { get; set; }
 
-        internal DataFrameColumnCollection(Action columnsChanged) : base()
-        {
-            ColumnsChanged = columnsChanged;
-        }
-
-        internal DataFrameColumnCollection(IList<DataFrameColumn> columns, Action columnsChanged) : base()
+        internal DataFrameColumnCollection(IEnumerable<DataFrameColumn> columns, Action columnsChanged) : base()
         {
             columns = columns ?? throw new ArgumentNullException(nameof(columns));
             ColumnsChanged = columnsChanged;
-            for (int i = 0; i < columns.Count; i++)
+            foreach (DataFrameColumn column in columns)
             {
-                Add(columns[i]);
+                Add(column);
             }
         }
 
diff --git a/tests/Microsoft.Data.Analysis.Tests/DataFrameTests.cs b/tests/Microsoft.Data.Analysis.Tests/DataFrameTests.cs
index 36bce6d754..b5ddefddd5 100644
--- a/tests/Microsoft.Data.Analysis.Tests/DataFrameTests.cs
+++ b/tests/Microsoft.Data.Analysis.Tests/DataFrameTests.cs
@@ -235,6 +235,12 @@ public void ColumnAndTableCreationTest()
             dataFrame.Columns.RemoveAt(1);
             Assert.Single(dataFrame.Columns);
             Assert.True(ReferenceEquals(intColumn, dataFrame.Columns[0]));
+
+            // Test the params constructor
+            DataFrame dataFrame1 = new DataFrame(intColumn, floatColumn);
+            Assert.Equal(2, dataFrame1.Columns.Count);
+            Assert.Equal(intColumn, dataFrame1.Columns[0]);
+            Assert.Equal(floatColumn, dataFrame1.Columns[1]);
         }
 
         [Fact]