fix ndarray to string.

src/TensorFlowNET.Core/Data/MnistModelLoader.cs

@@ -157,8 +157,8 @@ namespace Tensorflow
 
         private NDArray DenseToOneHot(NDArray labels_dense, int num_classes)
         {
-            var num_labels = labels_dense.dims[0];
-            var index_offset = np.arange(num_labels) * num_classes;
+            var num_labels = (int)labels_dense.dims[0];
+            // var index_offset = np.arange(num_labels) * num_classes;
             var labels_one_hot = np.zeros((num_labels, num_classes));
             var labels = labels_dense.ToArray<byte>();
             for (int row = 0; row < num_labels; row++)

src/TensorFlowNET.Core/Numpy/NDArray.cs

@@ -46,9 +46,6 @@ namespace Tensorflow.NumPy
         public byte[] ToByteArray() => BufferToArray();
         public static string[] AsStringArray(NDArray arr) => throw new NotImplementedException("");
 
-        public override string ToString()
-        {
-            return tensor_util.to_numpy_string(this);
-        }
+        public override string ToString() => tensor_util.to_numpy_string(this);
     }
 }

src/TensorFlowNET.Core/Tensors/tensor_util.cs

@@ -470,7 +470,7 @@ would not be rank 1.", tensor.op.get_attr("axis")));
             return ops.convert_to_tensor(shape, dtype: TF_DataType.TF_INT32, name: "shape");
         }
 
-        public static string to_numpy_string(Tensor array)
+        public static string to_numpy_string(NDArray array)
         {
             Shape shape = array.shape;
             if (shape.ndim == 0)
@@ -483,10 +483,66 @@ would not be rank 1.", tensor.op.get_attr("axis")));
             return s.ToString();
         }
 
-        static string Render(Tensor tensor)
+        static void PrettyPrint(StringBuilder s, NDArray array)
+        {
+            var shape = array.shape;
+
+            if (shape.Length == 1)
+            {
+                s.Append("[");
+                s.Append(Render(array));
+                s.Append("]");
+                return;
+            }
+
+            var len = shape[0];
+            s.Append("[");
+
+            if (len <= 10)
+            {
+                for (int i = 0; i < len; i++)
+                {
+                    PrettyPrint(s, array[i]);
+                    if (i < len - 1)
+                    {
+                        s.Append(", ");
+                        s.AppendLine();
+                    }
+                }
+            }
+            else
+            {
+                for (int i = 0; i < 5; i++)
+                {
+                    PrettyPrint(s, array[i]);
+                    if (i < len - 1)
+                    {
+                        s.Append(", ");
+                        s.AppendLine();
+                    }
+                }
+
+                s.Append(" ... ");
+                s.AppendLine();
+
+                for (int i = (int)len - 5; i < len; i++)
+                {
+                    PrettyPrint(s, array[i]);
+                    if (i < len - 1)
+                    {
+                        s.Append(", ");
+                        s.AppendLine();
+                    }
+                }
+            }
+
+            s.Append("]");
+        }
+
+        static string Render(NDArray tensor)
         {
             if (tensor.buffer == IntPtr.Zero)
-                return "Empty";
+                return "<null>";
 
             var dtype = tensor.dtype;
             var shape = tensor.shape;
@@ -508,48 +564,90 @@ would not be rank 1.", tensor.op.get_attr("axis")));
             {
                 return "<unprintable>";
             }
-            else if (dtype == TF_DataType.TF_BOOL)
-            {
-                var array = tensor.ToArray<bool>();
-                return DisplayArrayAsString(array, tensor.shape);
-            }
-            else if (dtype == TF_DataType.TF_INT32)
+            else
             {
-                var array = tensor.ToArray<int>();
-                return DisplayArrayAsString(array, tensor.shape);
+                return dtype switch
+                {
+                    TF_DataType.TF_BOOL => DisplayArrayAsString(tensor.ToArray<bool>(), tensor.shape),
+                    TF_DataType.TF_INT8 => DisplayArrayAsString(tensor.ToArray<sbyte>(), tensor.shape),
+                    TF_DataType.TF_INT32 => DisplayArrayAsString(tensor.ToArray<int>(), tensor.shape),
+                    TF_DataType.TF_INT64 => DisplayArrayAsString(tensor.ToArray<long>(), tensor.shape),
+                    TF_DataType.TF_FLOAT => DisplayArrayAsString(tensor.ToArray<float>(), tensor.shape),
+                    TF_DataType.TF_DOUBLE => DisplayArrayAsString(tensor.ToArray<double>(), tensor.shape),
+                    _ => DisplayArrayAsString(tensor.ToArray<byte>(), tensor.shape)
+                };
             }
-            else if (dtype == TF_DataType.TF_INT64)
+        }
+
+        public static string to_numpy_string(Tensor array)
+        {
+            Shape shape = array.shape;
+            if (shape.ndim == 0)
+                return array[0].ToString();
+
+            var s = new StringBuilder();
+            s.Append("array(");
+            PrettyPrint(s, array);
+            s.Append(")");
+            return s.ToString();
+        }
+
+        static string Render(Tensor tensor)
+        {
+            if (tensor.buffer == IntPtr.Zero)
+                return "<null>";
+
+            var dtype = tensor.dtype;
+            var shape = tensor.shape;
+
+            if (dtype == TF_DataType.TF_STRING)
             {
-                var array = tensor.ToArray<long>();
-                return DisplayArrayAsString(array, tensor.shape);
+                if (tensor.rank == 0)
+                    return "'" + string.Join(string.Empty, tensor.StringBytes()[0]
+                        .Take(25)
+                        .Select(x => x < 32 || x > 127 ? "\\x" + x.ToString("x") : Convert.ToChar(x).ToString())) + "'";
+                else
+                    return $"['{string.Join("', '", tensor.StringData().Take(25))}']";
             }
-            else if (dtype == TF_DataType.TF_FLOAT)
+            else if (dtype == TF_DataType.TF_VARIANT)
             {
-                var array = tensor.ToArray<float>();
-                return DisplayArrayAsString(array, tensor.shape);
+                return "<unprintable>";
             }
-            else if (dtype == TF_DataType.TF_DOUBLE)
+            else if (dtype == TF_DataType.TF_RESOURCE)
             {
-                var array = tensor.ToArray<double>();
-                return DisplayArrayAsString(array, tensor.shape);
+                return "<unprintable>";
             }
             else
             {
-                var array = tensor.ToArray<byte>();
-                return DisplayArrayAsString(array, tensor.shape);
+                return dtype switch
+                {
+                    TF_DataType.TF_BOOL => DisplayArrayAsString(tensor.ToArray<bool>(), tensor.shape),
+                    TF_DataType.TF_INT8 => DisplayArrayAsString(tensor.ToArray<sbyte>(), tensor.shape),
+                    TF_DataType.TF_INT32 => DisplayArrayAsString(tensor.ToArray<int>(), tensor.shape),
+                    TF_DataType.TF_INT64 => DisplayArrayAsString(tensor.ToArray<long>(), tensor.shape),
+                    TF_DataType.TF_FLOAT => DisplayArrayAsString(tensor.ToArray<float>(), tensor.shape),
+                    TF_DataType.TF_DOUBLE => DisplayArrayAsString(tensor.ToArray<double>(), tensor.shape),
+                    _ => DisplayArrayAsString(tensor.ToArray<byte>(), tensor.shape)
+                };
             }
         }
 
         static string DisplayArrayAsString<T>(T[] array, Shape shape)
         {
+            if (array == null)
+                return "<null>";
+
+            if (array.Length == 0)
+                return "<empty>";
+
             if (shape.ndim == 0)
                 return array[0].ToString();
 
             var display = "";
-            if (array.Length < 10)
+            if (array.Length <= 10)
                 display += string.Join(", ", array);
             else
-                display += string.Join(", ", array.Take(3)) + ", ..., " + string.Join(", ", array.Skip(array.Length - 3));
+                display += string.Join(", ", array.Take(5)) + ", ..., " + string.Join(", ", array.Skip(array.Length - 5));
             return display;
         }
 
@@ -597,7 +695,7 @@ would not be rank 1.", tensor.op.get_attr("axis")));
                 s.Append(" ... ");
                 s.AppendLine();
 
-                for (int i = (int)array.size - 5; i < len; i++)
+                for (int i = (int)len - 5; i < len; i++)
                 {
                     PrettyPrint(s, array[i], flat);
                     if (i < len - 1)