fix #19 by refactoring iterable checking

CHANGES.md

@@ -1,3 +1,6 @@
+# v0.1.2 #
+- fix issue #19 by refactoring the iterable checking into own function
+
 # v0.1.1 #
 - added support for saving more subsets and loading a certain one in/from a netcdf grid file
 - fix #15 by setting correct shape for derived cell grids

pygeogrids/grids.py

@@ -350,11 +350,7 @@ def find_nearest_gpi(self, lon, lat, max_dist=np.Inf):
             At the moment not on a great circle but in spherical cartesian coordinates
         """
         # check if input is iterable
-        try:
-            lon[0]
-            iterable = True
-        except TypeError:
-            iterable = False
+        iterable = _element_iterable(lon)
 
         if self.kdTree is None:
             self._setup_kdtree()
@@ -411,11 +407,8 @@ def gpi2rowcol(self, gpi):
             column in 2D array
         """
         # check if iterable
-        try:
-            gpi[0]
-            iterable = True
-        except (TypeError, IndexError):
-            iterable = False
+        iterable = _element_iterable(gpi)
+
         gpi = np.atleast_1d(gpi)
         if len(self.shape) == 2:
             if self.gpidirect:
@@ -660,11 +653,8 @@ def gpi2cell(self, gpi):
             Cell number of GPI.
         """
         # check if iterable
-        try:
-            gpi[0]
-            iterable = True
-        except TypeError:
-            iterable = False
+        iterable = _element_iterable(gpi)
+
         gpi = np.atleast_1d(gpi)
         if self.gpidirect:
             cell = self.arrcell[gpi]
@@ -914,3 +904,27 @@ def genreg_grid(grd_spc_lat=1, grd_spc_lon=1,
     lat_dim = np.arange(maxlat - grd_spc_lat / 2.0, minlat, -grd_spc_lat)
 
     return gridfromdims(lon_dim, lat_dim)
+
+
+def _element_iterable(el):
+    """
+    Test if a element is iterable
+
+    Parameters
+    ----------
+    el: object
+
+
+    Returns
+    -------
+    iterable: boolean
+       if True then then el is iterable
+       if Fales then not
+    """
+    try:
+        el[0]
+        iterable = True
+    except (TypeError, IndexError):
+        iterable = False
+
+    return iterable

tests/test_grid.py

@@ -67,6 +67,14 @@ def test_nearest_neighbor_ndarray(self):
         assert lat[0] == 45.5
         assert lat[1] == -16.5
 
+    def test_nearest_neighbor_numpy_single(self):
+        gpi, dist = self.grid.find_nearest_gpi(
+            np.array([145.1, 90.2])[0], np.array([45.8, -16.3])[0])
+        assert gpi == 16165
+        lon, lat = self.grid.gpi2lonlat(gpi)
+        assert lon == 145.5
+        assert lat == 45.5
+
 
 class TestCellGrid(unittest.TestCase):
 
@@ -100,6 +108,14 @@ def test_gpi2cell_iterable(self):
         cell = self.cellgrid.gpi2cell(gpi)
         assert np.all(cell == [1043, 2015])
 
+    def test_gpi2cell_numpy_single(self):
+        """
+        test if gpi to row column lookup works correctly
+        """
+        gpi = np.array([200, 255])[0]
+        cell = self.cellgrid.gpi2cell(gpi)
+        assert cell == 1043
+
     def test_gpi2cell_custom_gpis(self):
         """
         test if gpi to row column lookup works correctly