fix cifar label dimension. test=develop (#33475)

python/paddle/tests/test_dataset_cifar.py

@@ -32,6 +32,8 @@ class TestCifar10Train(unittest.TestCase):
         self.assertTrue(data.shape[2] == 3)
         self.assertTrue(data.shape[1] == 32)
         self.assertTrue(data.shape[0] == 32)
+        self.assertTrue(len(label.shape) == 1)
+        self.assertTrue(label.shape[0] == 1)
         self.assertTrue(0 <= int(label) <= 9)
 
 
@@ -49,6 +51,8 @@ class TestCifar10Test(unittest.TestCase):
         self.assertTrue(data.shape[2] == 3)
         self.assertTrue(data.shape[1] == 32)
         self.assertTrue(data.shape[0] == 32)
+        self.assertTrue(len(label.shape) == 1)
+        self.assertTrue(label.shape[0] == 1)
         self.assertTrue(0 <= int(label) <= 9)
 
         # test cv2 backend
@@ -63,6 +67,8 @@ class TestCifar10Test(unittest.TestCase):
         self.assertTrue(data.shape[2] == 3)
         self.assertTrue(data.shape[1] == 32)
         self.assertTrue(data.shape[0] == 32)
+        self.assertTrue(len(label.shape) == 1)
+        self.assertTrue(label.shape[0] == 1)
         self.assertTrue(0 <= int(label) <= 99)
 
         with self.assertRaises(ValueError):
@@ -83,6 +89,8 @@ class TestCifar100Train(unittest.TestCase):
         self.assertTrue(data.shape[2] == 3)
         self.assertTrue(data.shape[1] == 32)
         self.assertTrue(data.shape[0] == 32)
+        self.assertTrue(len(label.shape) == 1)
+        self.assertTrue(label.shape[0] == 1)
         self.assertTrue(0 <= int(label) <= 99)
 
 
@@ -100,6 +108,8 @@ class TestCifar100Test(unittest.TestCase):
         self.assertTrue(data.shape[2] == 3)
         self.assertTrue(data.shape[1] == 32)
         self.assertTrue(data.shape[0] == 32)
+        self.assertTrue(len(label.shape) == 1)
+        self.assertTrue(label.shape[0] == 1)
         self.assertTrue(0 <= int(label) <= 99)
 
         # test cv2 backend
@@ -114,6 +124,8 @@ class TestCifar100Test(unittest.TestCase):
         self.assertTrue(data.shape[2] == 3)
         self.assertTrue(data.shape[1] == 32)
         self.assertTrue(data.shape[0] == 32)
+        self.assertTrue(len(label.shape) == 1)
+        self.assertTrue(label.shape[0] == 1)
         self.assertTrue(0 <= int(label) <= 99)
 
         with self.assertRaises(ValueError):

python/paddle/vision/datasets/cifar.py

@@ -151,7 +151,8 @@ class Cifar10(Dataset):
                     six.b('labels'), batch.get(six.b('fine_labels'), None))
                 assert labels is not None
                 for sample, label in six.moves.zip(data, labels):
-                    self.data.append((sample, label))
+                    self.data.append((sample,
+                                      np.array([label]).astype('int64')))
 
     def __getitem__(self, idx):
         image, label = self.data[idx]
@@ -164,9 +165,9 @@ class Cifar10(Dataset):
             image = self.transform(image)
 
         if self.backend == 'pil':
-            return image, np.array(label).astype('int64')
+            return image, label.astype('int64')
 
-        return image.astype(self.dtype), np.array(label).astype('int64')
+        return image.astype(self.dtype), label.astype('int64')
 
     def __len__(self):
         return len(self.data)