Improved repr of ArraySequence

Author: MarcCote

nibabel/streamlines/array_sequence.py

@@ -263,7 +263,17 @@ def __len__(self):
         return len(self._offsets)
 
     def __repr__(self):
-        return repr(list(self))
+        if len(self) > np.get_printoptions()['threshold']:
+            # Show only the first and last edgeitems.
+            edgeitems = np.get_printoptions()['edgeitems']
+            data = str(list(self[:edgeitems]))[:-1]
+            data += ", ..., "
+            data += str(list(self[-edgeitems:]))[1:]
+        else:
+            data = str(list(self))
+
+        return "{name}({data})".format(name=self.__class__.__name__,
+                                       data=data)
 
     def save(self, filename):
         """ Saves this :class:`ArraySequence` object to a .npz file. """

nibabel/streamlines/tests/test_array_sequence.py

@@ -249,6 +249,20 @@ def test_arraysequence_repr(self):
         # Test that calling repr on a ArraySequence object is not falling.
         repr(SEQ_DATA['seq'])
 
+        # Test calling repr when the number of arrays is bigger dans Numpy's
+        # print option threshold.
+        nb_arrays = 50
+        seq = ArraySequence(generate_data(nb_arrays, common_shape=(1,),
+                                          rng=SEQ_DATA['rng']))
+
+        bkp_threshold = np.get_printoptions()['threshold']
+        np.set_printoptions(threshold=nb_arrays*2)
+        txt1 = repr(seq)
+        np.set_printoptions(threshold=nb_arrays//2)
+        txt2 = repr(seq)
+        assert_true(len(txt2) < len(txt1))
+        np.set_printoptions(threshold=bkp_threshold)
+
     def test_save_and_load_arraysequence(self):
         # Test saving and loading an empty ArraySequence.
         with tempfile.TemporaryFile(mode="w+b", suffix=".npz") as f: