Added convenience constructor for set of transforms (#380).

src/Microsoft.ML.Data/Transforms/ConcatTransform.cs

@@ -90,6 +90,19 @@ public bool TryUnparse(StringBuilder sb)
 
         public sealed class Arguments : TransformInputBase
         {
+            public Arguments()
+            {
+            }
+
+            public Arguments(string name, params string[] source)
+            {
+                Column = new[] { new Column()
+                {
+                    Name = name,
+                    Source = source
+                }};
+            }
+
             [Argument(ArgumentType.Multiple | ArgumentType.Required, HelpText = "New column definition(s) (optional form: name:srcs)", ShortName = "col", SortOrder = 1)]
             public Column[] Column;
         }
@@ -527,6 +540,18 @@ private static VersionInfo GetVersionInfo()
 
         public override ISchema Schema => _bindings;
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Input columns to concatenate.</param>
+        public ConcatTransform(IHostEnvironment env, IDataView input, string name, params string[] source)
+            : this(env, new Arguments(name, source), input)
+        {
+        }
+
         /// <summary>
         /// Public constructor corresponding to SignatureDataTransform.
         /// </summary>

src/Microsoft.ML.Data/Transforms/CopyColumnsTransform.cs

@@ -64,6 +64,19 @@ private static VersionInfo GetVersionInfo()
 
         private const string RegistrationName = "CopyColumns";
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be copied.</param>
+        public CopyColumnsTransform(IHostEnvironment env, IDataView input, string name, string source)
+            : this(env, new Arguments(){ Column = new[] { new Column() { Source = source, Name = name }}}, input)
+        {
+
+        }
+
         public CopyColumnsTransform(IHostEnvironment env, Arguments args, IDataView input)
             : base(env, RegistrationName, env.CheckRef(args, nameof(args)).Column, input, null)
         {

src/Microsoft.ML.Data/Transforms/DropColumnsTransform.cs

@@ -237,6 +237,17 @@ private static VersionInfo GetVersionInfo()
         private const string DropRegistrationName = "DropColumns";
         private const string KeepRegistrationName = "KeepColumns";
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="columnsToDrop">Name of the columns to be dropped.</param>
+        public DropColumnsTransform(IHostEnvironment env, IDataView input, params string[] columnsToDrop)
+         :this(env, new Arguments() { Column = columnsToDrop }, input)
+        {
+        }
+
         /// <summary>
         /// Public constructor corresponding to SignatureDataTransform.
         /// </summary>
@@ -383,4 +394,17 @@ public ValueGetter<TValue> GetGetter<TValue>(int col)
             }
         }
     }
+
+    public class KeepColumnsTransform
+    {
+        /// <summary>
+        /// A helper method to create <see cref="KeepColumnsTransform"/> for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="columnsToKeep">Name of the columns to be kept. All other columns will be removed.</param>
+        /// <returns></returns>
+        public static IDataTransform Create(IHostEnvironment env, IDataView input, params string[] columnsToKeep)
+            => new DropColumnsTransform(env, new DropColumnsTransform.KeepArguments() { Column = columnsToKeep }, input);
+    }
 }

src/Microsoft.ML.Data/Transforms/NAFilter.cs

@@ -72,6 +72,19 @@ private static VersionInfo GetVersionInfo()
         private readonly bool _complement;
         private const string RegistrationName = "MissingValueFilter";
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="complement">If true, keep only rows that contain NA values, and filter the rest.</param>
+        /// <param name="columns">Name of the columns. Only these columns will be used to filter rows having 'NA' values.</param>
+        public NAFilter(IHostEnvironment env, IDataView input, bool complement = false, params string[] columns)
+            : this(env, new Arguments() { Column = columns, Complement = complement }, input)
+        {
+
+        }
+
         public NAFilter(IHostEnvironment env, Arguments args, IDataView input)
             : base(env, RegistrationName, input)
         {

src/Microsoft.ML.Transforms/BootstrapSampleTransform.cs

@@ -76,6 +76,21 @@ public BootstrapSampleTransform(IHostEnvironment env, Arguments args, IDataView
             _poolSize = args.PoolSize;
         }
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="complement">Whether this is the out-of-bag sample, that is, all those rows that are not selected by the transform.</param>
+        /// <param name="seed">The random seed. If unspecified random state will be instead derived from the environment.</param>
+        /// <param name="shuffleInput">Whether we should attempt to shuffle the source data. By default on, but can be turned off for efficiency.</param>
+        /// <param name="poolSize">When shuffling the output, the number of output rows to keep in that pool. Note that shuffling of output is completely distinct from shuffling of input.</param>
+        public BootstrapSampleTransform(IHostEnvironment env, IDataView input, bool complement = false, uint? seed = null, bool shuffleInput = true, int poolSize = 1000)
+            : this(env, new Arguments() { Complement = complement, Seed = seed, ShuffleInput = shuffleInput, PoolSize = poolSize }, input)
+        {
+
+        }
+
         private BootstrapSampleTransform(IHost host, ModelLoadContext ctx, IDataView input)
             : base(host, input)
         {

src/Microsoft.ML.Transforms/CategoricalHashTransform.cs

@@ -120,6 +120,32 @@ public sealed class Arguments : TransformInputBase
 
         public const string UserName = "Categorical Hash Transform";
 
+        /// <summary>
+        /// A helper method to create <see cref="CategoricalHashTransform"/> for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        /// <param name="hashBits">Number of bits to hash into. Must be between 1 and 30, inclusive.</param>
+        /// <param name="invertHash">Limit the number of keys used to generate the slot name to this many. 0 means no invert hashing, -1 means no limit.</param>
+        /// <param name="outputKind">Output kind: Bag (multi-set vector), Ind (indicator vector), or Key (index).</param>
+        public static IDataTransform Create(IHostEnvironment env, IDataView input, string name, string source =null, int hashBits = 16, int invertHash = 0, CategoricalTransform.OutputKind outputKind = CategoricalTransform.OutputKind.Bag)
+        {
+            var args = new Arguments()
+            {
+                Column = new[] { new Column(){
+                    Source = source ?? name,
+                    Name = name
+                    }
+                },
+                HashBits = hashBits,
+                InvertHash = invertHash,
+                OutputKind = outputKind
+            };
+            return Create(env, args, input);
+        }
+
         public static IDataTransform Create(IHostEnvironment env, Arguments args, IDataView input)
         {
             Contracts.CheckValue(env, nameof(env));

src/Microsoft.ML.Transforms/CategoricalTransform.cs

@@ -118,6 +118,28 @@ public Arguments()
 
         public const string UserName = "Categorical Transform";
 
+        /// <summary>
+        /// A helper method to create <see cref="CategoricalTransform"/> for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        /// <param name="outputKind">Output kind: Bag (multi-set vector), Ind (indicator vector), or Key (index).</param>
+        public static IDataTransform Create(IHostEnvironment env, IDataView input, string name, string source = null, OutputKind outputKind = OutputKind.Ind)
+        {
+            var args = new Arguments()
+            {
+                Column = new[] { new Column(){
+                        Source = source ?? name,
+                        Name = name
+                    }
+                },
+                OutputKind = outputKind
+            };
+            return Create(env, args, input);
+        }
+
         public static IDataTransform Create(IHostEnvironment env, Arguments args, IDataView input)
         {
             Contracts.CheckValue(env, nameof(env));

src/Microsoft.ML.Transforms/CountFeatureSelection.cs

@@ -39,6 +39,24 @@ public sealed class Arguments : TransformInputBase
 
         internal static string RegistrationName = "CountFeatureSelectionTransform";
 
+        /// <summary>
+        /// A helper method to create CountFeatureSelection transform for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="count">If the count of non-default values for a slot is greater than or equal to this threshold, the slot is preserved.</param>
+        /// <param name="columns">Columns to use for feature selection.</param>
+        /// <returns></returns>
+        public static IDataTransform Create(IHostEnvironment env, IDataView input, long count = 1, params string[] columns)
+        {
+            var args = new Arguments()
+            {
+                Column = columns,
+                Count = count
+            };
+            return Create(env, args, input);
+        }
+
         /// <summary>
         /// Create method corresponding to SignatureDataTransform.
         /// </summary>

src/Microsoft.ML.Transforms/GcnTransform.cs

@@ -237,6 +237,32 @@ private static VersionInfo GetVersionInfo()
 
         private readonly ColInfoEx[] _exes;
 
+        /// <summary>
+        /// A helper method to create GlobalContrastNormalizer transform for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        /// <param name="subMean">Subtract mean from each value before normalizing.</param>
+        /// <param name="useStdDev">Normalize by standard deviation rather than L2 norm.</param>
+        /// <param name="scale">Scale features by this value.</param>
+        public static IDataTransform CreateGlobalContrastNormalizer(IHostEnvironment env, IDataView input, string name, string source = null, bool subMean = true, bool useStdDev = false, Float scale = 1)
+        {
+            var args = new GcnArguments()
+            {
+                Column = new[] { new GcnColumn(){
+                        Source = source ?? name,
+                        Name = name
+                    }
+                },
+                SubMean = subMean,
+                UseStdDev = useStdDev,
+                Scale = scale
+            };
+            return new LpNormNormalizerTransform(env, args, input);
+        }
+
         /// <summary>
         /// Public constructor corresponding to SignatureDataTransform.
         /// </summary>
@@ -263,9 +289,33 @@ public LpNormNormalizerTransform(IHostEnvironment env, GcnArguments args, IDataV
             SetMetadata();
         }
 
+        /// <summary>
+        /// A helper method to create LpNormNormalizer transform for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        ///         /// <param name="normKind">The norm to use to normalize each sample.</param>
+        /// <param name="subMean">Subtract mean from each value before normalizing.</param>
+        public static IDataTransform CreateLpNormNormalizer(IHostEnvironment env, IDataView input, string name, string source = null, NormalizerKind normKind = NormalizerKind.L2Norm, bool subMean = false)
+        {
+            var args = new Arguments()
+            {
+                Column = new[] { new Column(){
+                        Source = source ?? name,
+                        Name = name
+                    }
+                },
+                SubMean = subMean,
+                NormKind = normKind
+            };
+            return new LpNormNormalizerTransform(env, args, input);
+        }
+
         public LpNormNormalizerTransform(IHostEnvironment env, Arguments args, IDataView input)
-            : base(env, RegistrationName, env.CheckRef(args, nameof(args)).Column,
-                input, TestIsFloatVector)
+        : base(env, RegistrationName, env.CheckRef(args, nameof(args)).Column,
+            input, TestIsFloatVector)
         {
             Host.AssertNonEmpty(Infos);
             Host.Assert(Infos.Length == Utils.Size(args.Column));

src/Microsoft.ML.Transforms/NormalizeColumn.cs

@@ -218,6 +218,26 @@ public sealed class SupervisedBinArguments : BinArgumentsBase
         public const string BinNormalizerShortName = "Bin";
         public const string SupervisedBinNormalizerShortName = "SupBin";
 
+        /// <summary>
+        /// A helper method to create MinMaxNormalizer transform for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        public static NormalizeTransform CreateMinMaxNormalizer(IHostEnvironment env, IDataView input, string name, string source = null)
+        {
+            var args = new MinMaxArguments()
+            {
+                Column = new[] { new AffineColumn(){
+                        Source = source ?? name,
+                        Name = name
+                    }
+                }
+            };
+            return Create(env, args, input);
+        }
+
         /// <summary>
         /// Public create method corresponding to SignatureDataTransform.
         /// </summary>
@@ -234,6 +254,28 @@ public static NormalizeTransform Create(IHostEnvironment env, MinMaxArguments ar
             return func;
         }
 
+        /// <summary>
+        /// A helper method to create MeanVarNormalizer transform for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        /// /// <param name="useCdf">Whether to use CDF as the output.</param>
+        public static NormalizeTransform CreateMeanVarNormalizer(IHostEnvironment env, IDataView input, string name, string source=null, bool useCdf = false)
+        {
+            var args = new MeanVarArguments()
+            {
+                Column = new[] { new AffineColumn(){
+                        Source = source ?? name,
+                        Name = name
+                    }
+                },
+                UseCdf = useCdf
+            };
+            return Create(env, args, input);
+        }
+
         /// <summary>
         /// Public create method corresponding to SignatureDataTransform.
         /// </summary>
@@ -250,6 +292,28 @@ public static NormalizeTransform Create(IHostEnvironment env, MeanVarArguments a
             return func;
         }
 
+        /// <summary>
+        /// A helper method to create LogMeanVarNormalizer transform for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        /// /// <param name="useCdf">Whether to use CDF as the output.</param>
+        public static NormalizeTransform CreateLogMeanVarNormalizer(IHostEnvironment env, IDataView input, string name, string source=null, bool useCdf = true)
+        {
+            var args = new LogMeanVarArguments()
+            {
+                Column = new[] { new LogNormalColumn(){
+                        Source = source ?? name,
+                        Name = name
+                    }
+                },
+                UseCdf = useCdf
+            };
+            return Create(env, args, input);
+        }
+
         /// <summary>
         /// Public create method corresponding to SignatureDataTransform.
         /// </summary>
@@ -266,6 +330,20 @@ public static NormalizeTransform Create(IHostEnvironment env, LogMeanVarArgument
             return func;
         }
 
+        public static NormalizeTransform CreateBinningNormalizer(IHostEnvironment env, IDataView input, string name, string source=null, int numBins = 1024)
+        {
+            var args = new BinArguments()
+            {
+                Column = new[] { new BinColumn(){
+                        Source = source ?? name,
+                        Name = name
+                    }
+                },
+                NumBins = numBins
+            };
+            return Create(env, args, input);
+        }
+
         /// <summary>
         /// Public create method corresponding to SignatureDataTransform.
         /// </summary>