pass tests

Author: rcomer

lib/iris/coords.py

@@ -1951,24 +1951,36 @@ def collapsed(self, dims_to_collapse=None):
         if np.issubdtype(self.dtype, np.str_):
             # Collapse the coordinate by serializing the points and
             # bounds as strings.
-            def serialize(x):
-                return "|".join([str(i) for i in x.flatten()])
+            def serialize(x, axis):
+                if axis is None:
+                    return "|".join(x.flatten())
+                # np.apply_along_axis does not work with str.join, so we
+                # need to loop through the array directly. First move (possibly
+                # multiple) axis of interest to trailing dims, then make a 2D
+                # array we can loop through.
+                work_array = np.moveaxis(x, axis, range(-len(axis), 0))
+                out_shape = work_array.shape[: -len(axis)]
+                work_array = work_array.reshape(np.prod(out_shape), -1)
+
+                joined = []
+                for arr_slice in work_array:
+                    joined.append("|".join(arr_slice))
+
+                return np.array(joined).reshape(out_shape)
 
             bounds = None
             if self.has_bounds():
-                shape = self._bounds_dm.shape[1:]
+                shape = self._bounds_dm.shape[-1:]
                 bounds = []
                 for index in np.ndindex(shape):
                     index_slice = (slice(None),) + tuple(index)
-                    bounds.append(serialize(self.bounds[index_slice]))
-                dtype = np.dtype("U{}".format(max(map(len, bounds))))
-                bounds = np.array(bounds, dtype=dtype).reshape((1,) + shape)
-            points = serialize(self.points)
-            dtype = np.dtype("U{}".format(len(points)))
+                    bounds.append(
+                        serialize(self.bounds[index_slice], dims_to_collapse)
+                    )
+                bounds = np.array(bounds).reshape((1,) + shape)
+            points = serialize(self.points, dims_to_collapse)
             # Create the new collapsed coordinate.
-            coord = self.copy(
-                points=np.array(points, dtype=dtype), bounds=bounds
-            )
+            coord = self.copy(points=np.array(points), bounds=bounds)
         else:
             # Collapse the coordinate by calculating the bounded extremes.
             if self.ndim > 1:

lib/iris/tests/unit/coords/test_Coord.py

@@ -478,7 +478,7 @@ def test_string_nd_first(self):
             "0.0|40.0|80.0",
             "10.0|50.0|90.0",
             "20.0|60.0|100.0",
-            "30.0|70.0|111.0",
+            "30.0|70.0|110.0",
         ]
 
         self.assertArrayEqual(collapsed_coord.points, expected)