fix string data.

src/TensorFlowNET.Core/NumPy/NDArray.Implicit.cs

@@ -37,7 +37,7 @@ namespace Tensorflow.NumPy
             => new NDArray(value);
 
         public static implicit operator Tensor(NDArray nd)
-            => constant_op.constant(nd);
+            => nd._tensor;
 
         public static implicit operator NDArray(Tensor tensor)
             => new NDArray(tensor);

src/TensorFlowNET.Core/Tensors/Tensor.Value.cs

@@ -49,8 +49,12 @@ namespace Tensorflow
 
         protected NDArray GetNDArray(TF_DataType dtype)
         {
-            /*if (dtype == TF_DataType.TF_STRING)
-                return np.array(StringData());*/
+            if (dtype == TF_DataType.TF_STRING)
+            {
+                var str= StringData();
+                return new NDArray(str, new Shape(str.Length));
+            }
+                
             return new NDArray(this);
         }
 

src/TensorFlowNET.Core/ops.cs

@@ -171,6 +171,9 @@ namespace Tensorflow
                 _ => constant_op.constant(value, dtype: dtype, name: name)
             };
 
+            if (dtype == TF_DataType.TF_STRING)
+                return ret;
+
             var original_dtype = value.GetDataType();
             if (dtype != TF_DataType.DtInvalid && dtype != original_dtype)
                 ret = gen_math_ops.cast(ret, dtype.as_base_dtype(), name: name);