Resolve inconsistency in IMDB label output (#1914)

Author: Nayef211

test/torchtext_unittest/datasets/test_imdb.py

@@ -29,8 +29,8 @@ def _get_mock_dataset(root_dir):
         for i in range(5):
             # all negative labels are read first before positive labels in the
             # IMDB dataset implementation
-            label = "neg" if i < 2 else "pos"
-            cur_dir = pos_dir if label == "pos" else neg_dir
+            label = 1 if i < 2 else 2
+            cur_dir = pos_dir if label == 2 else neg_dir
             txt_file = os.path.join(cur_dir, f"{i}{i}_{i}.txt")
             with open(txt_file, "w", encoding="utf-8") as f:
                 rand_string = get_random_unicode(seed)

torchtext/datasets/imdb.py

@@ -20,6 +20,8 @@
     "test": 25000,
 }
 
+MAP_LABELS = {"neg": 1, "pos": 2}
+
 _PATH = "aclImdb_v1.tar.gz"
 
 DATASET_NAME = "IMDB"
@@ -50,7 +52,7 @@ def _cache_filepath_fn(root, decompressed_folder, split, x):
 
 
 def _modify_res(t):
-    return Path(t[0]).parts[-1], t[1]
+    return MAP_LABELS[Path(t[0]).parts[-1]], t[1]
 
 
 def filter_imdb_data(key, fname):