fix: DocVec display (docarray#1522)

Signed-off-by: AnneY <evangeline-lun@foxmail.com>

docarray/array/doc_vec/column_storage.py

@@ -140,3 +140,6 @@ def __iter__(self):
 
     def __len__(self):
         return len(self.storage.columns)
+
+    def keys(self):
+        return self.storage.columns.keys()

docarray/base_doc/doc.py

@@ -104,8 +104,17 @@ def _get_field_type(cls, field: str) -> Type:
         return cls.__fields__[field].outer_type_
 
     def __str__(self) -> str:
+        content: Any = None
+        if self.is_view():
+            attr_str = ", ".join(
+                f"{field}={self.__getattr__(field)}" for field in self.__dict__.keys()
+            )
+            content = f"{self.__class__.__name__}({attr_str})"
+        else:
+            content = self
+
         with _console.capture() as capture:
-            _console.print(self)
+            _console.print(content)
 
         return capture.get().strip()
 

tests/units/document/test_view.py

@@ -13,7 +13,14 @@ class MyDoc(BaseDoc):
 
     docs = [MyDoc(tensor=np.zeros((10, 10)), name='hello', id=i) for i in range(4)]
 
-    storage = DocVec[MyDoc](docs)._storage
+    doc_vec = DocVec[MyDoc](docs)
+    storage = doc_vec._storage
+
+    result = str(doc_vec[0])
+    assert 'MyDoc' in result
+    assert 'id' in result
+    assert 'tensor' in result
+    assert 'name' in result
 
     doc = MyDoc.from_view(ColumnStorageView(0, storage))
     assert doc.is_view()