Cast by using is operator

docs/samples/Microsoft.ML.Samples/Dynamic/Transforms/CustomMappingWithInMemoryCustomType.cs

@@ -106,8 +106,8 @@ public override void Register()
 
             public override bool Equals(DataViewTypeAttribute other)
             {
-                if (other is AlienTypeAttributeAttribute)
-                    return RaceId == ((AlienTypeAttributeAttribute)other).RaceId;
+                if (other is AlienTypeAttributeAttribute alienTypeAttributeAttribute)
+                    return RaceId == alienTypeAttributeAttribute.RaceId;
                 return false;
             }
 

src/Microsoft.ML.Data/DataView/Transposer.cs

@@ -266,10 +266,10 @@ VectorDataViewType ITransposeDataView.GetSlotType(int col)
 
             var transposedColumn = _view.Schema[col];
             PrimitiveDataViewType elementType = null;
-            if (transposedColumn.Type is PrimitiveDataViewType)
-                elementType = (PrimitiveDataViewType)transposedColumn.Type;
-            else if (transposedColumn.Type is VectorDataViewType)
-                elementType = ((VectorDataViewType)transposedColumn.Type).ItemType;
+            if (transposedColumn.Type is PrimitiveDataViewType primitiveDataViewType)
+                elementType = primitiveDataViewType;
+            else if (transposedColumn.Type is VectorDataViewType vectorDataViewType)
+                elementType = vectorDataViewType.ItemType;
             _host.Assert(elementType != null);
 
             return new VectorDataViewType(elementType, RowCount);

src/Microsoft.ML.FastTree/TreeEnsembleFeaturizer.cs

@@ -707,8 +707,8 @@ public static IDataTransform CreateForEntryPoint(IHostEnvironment env, Arguments
                 ch.Assert(predictor == predictor2);
 
                 // Make sure that the given predictor has the correct number of input features.
-                if (predictor is CalibratedModelParametersBase<IPredictorProducing<float>, Calibrators.ICalibrator>)
-                    predictor = ((CalibratedModelParametersBase<IPredictorProducing<float>, Calibrators.ICalibrator>)predictor).SubModel;
+                if (predictor is CalibratedModelParametersBase<IPredictorProducing<float>, Calibrators.ICalibrator> calibratedModelParametersBase)
+                    predictor = calibratedModelParametersBase.SubModel;
                 // Predictor should be a TreeEnsembleModelParameters, which implements IValueMapper, so this should
                 // be non-null.
                 var vm = predictor as IValueMapper;

src/Microsoft.ML.TimeSeries/PredictionEngine.cs

@@ -110,12 +110,10 @@ public void CheckPoint(IHostEnvironment env, Stream stream)
             Contracts.CheckValue(env, nameof(env));
             env.CheckParam(stream != null, nameof(stream));
 
-            if (Transformer is ITransformerChainAccessor)
+            if (Transformer is ITransformerChainAccessor transformerChainAccessor)
             {
 
-                new TransformerChain<ITransformer>
-                (((ITransformerChainAccessor)Transformer).Transformers,
-                ((ITransformerChainAccessor)Transformer).Scopes).SaveTo(env, stream);
+                new TransformerChain<ITransformer>(transformerChainAccessor.Transformers, transformerChainAccessor.Scopes).SaveTo(env, stream);
             }
             else
                 Transformer.SaveTo(env, stream);
@@ -125,9 +123,9 @@ private static ITransformer CloneTransformers(ITransformer transformer)
         {
             ITransformer[] transformersClone = null;
             TransformerScope[] scopeClone = null;
-            if (transformer is ITransformerChainAccessor)
+            if (transformer is ITransformerChainAccessor transformerChainAccessor)
             {
-                ITransformerChainAccessor accessor = (ITransformerChainAccessor)transformer;
+                ITransformerChainAccessor accessor = transformerChainAccessor;
                 transformersClone = accessor.Transformers.Select(x => x).ToArray();
                 scopeClone = accessor.Scopes.Select(x => x).ToArray();
                 int index = 0;
@@ -220,8 +218,8 @@ private protected override void PredictionEngineCore(IHostEnvironment env, DataV
 
         private bool IsRowToRowMapper(ITransformer transformer)
         {
-            if (transformer is ITransformerChainAccessor)
-                return ((ITransformerChainAccessor)transformer).Transformers.All(t => t.IsRowToRowMapper || t is IStatefulTransformer);
+            if (transformer is ITransformerChainAccessor transformerChainAccessor)
+                return transformerChainAccessor.Transformers.All(t => t.IsRowToRowMapper || t is IStatefulTransformer);
             else
                 return transformer.IsRowToRowMapper || transformer is IStatefulTransformer;
         }
@@ -233,8 +231,8 @@ private IRowToRowMapper GetRowToRowMapper(DataViewSchema inputSchema)
                 " method called despite " + nameof(IsRowToRowMapper) + " being false. or transformer not being " + nameof(IStatefulTransformer));
 
             if (!(InputTransformer is ITransformerChainAccessor))
-                if (InputTransformer is IStatefulTransformer)
-                    return ((IStatefulTransformer)InputTransformer).GetStatefulRowToRowMapper(inputSchema);
+                if (InputTransformer is IStatefulTransformer statefulTransformer)
+                    return statefulTransformer.GetStatefulRowToRowMapper(inputSchema);
                 else
                     return InputTransformer.GetRowToRowMapper(inputSchema);
 

test/Microsoft.ML.Core.Tests/UnitTests/TestCustomTypeRegister.cs

@@ -64,8 +64,8 @@ public override void Register()
 
             public override bool Equals(DataViewTypeAttribute other)
             {
-                if (other is AlienTypeAttributeAttribute)
-                    return RaceId == ((AlienTypeAttributeAttribute)other).RaceId;
+                if (other is AlienTypeAttributeAttribute alienTypeAttributeAttribute)
+                    return RaceId == alienTypeAttributeAttribute.RaceId;
                 return false;
             }