psyplot · Chilipp · Apr 9, 2020 · Apr 9, 2020 · Apr 9, 2020 · Apr 9, 2020
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
@@ -2,6 +2,11 @@ v1.2.2
 ======
 Added
 -----
+* ``ArrayList.from_dataset`` (and consecutively all plotmethods) now support
+  different input types for the decoder. You can pass an instance of the
+  ``CFDecoder`` class, a sub class of ``CFDecoder``, or keyword arguments
+  that are used to initialize the decoder,
+  see `#20 <https://github.com/psyplot/psyplot/pull/20>`__
 * `psyplot.data.open_dataset` now decodes grid_mappings attributes,
 see `#17 <https://github.com/psyplot/psyplot/pull/17>`__
 * psyplot projects now support the with syntax, e.g. something like::
@@ -20,6 +25,8 @@ Changed
   are ignored
 * If a given variable cannot be found in the provided coords to ``CFDecoder.get_variable_by_axis``,
   we fall back to the ``CFDecoder.ds.coords`` attribute, see `#19 <https://github.com/psyplot/psyplot/pull/19>`__
+* A bug has been fixed for initializing a ``CFDecoder`` with ``x, y, z`` and
+  ``t`` parameters (see `#20 <https://github.com/psyplot/psyplot/pull/20>`__)
 
 
 v1.2.1

diff --git a/psyplot/data.py b/psyplot/data.py
@@ -550,9 +550,9 @@ def logger(self, value):
     def __init__(self, ds=None, x=None, y=None, z=None, t=None):
         self.ds = ds
         self.x = rcParams['decoder.x'].copy() if x is None else set(x)
-        self.y = rcParams['decoder.y'].copy() if x is None else set(y)
-        self.z = rcParams['decoder.z'].copy() if x is None else set(z)
-        self.t = rcParams['decoder.t'].copy() if x is None else set(t)
+        self.y = rcParams['decoder.y'].copy() if y is None else set(y)
+        self.z = rcParams['decoder.z'].copy() if z is None else set(z)
+        self.t = rcParams['decoder.t'].copy() if t is None else set(t)
 
     @staticmethod
     def register_decoder(decoder_class, pos=0):
@@ -599,7 +599,7 @@ def can_decode(cls, ds, var):
 
     @classmethod
     @docstrings.dedent
-    def get_decoder(cls, ds, var):
+    def get_decoder(cls, ds, var, *args, **kwargs):
         """
         Class method to get the right decoder class that can decode the
         given dataset and variable
@@ -615,8 +615,8 @@ def get_decoder(cls, ds, var):
             `var`"""
         for decoder_cls in cls._registry:
             if decoder_cls.can_decode(ds, var):
-                return decoder_cls(ds)
-        return CFDecoder(ds)
+                return decoder_cls(ds, *args, **kwargs)
+        return CFDecoder(ds, *args, **kwargs)
 
     @staticmethod
     @docstrings.get_sectionsf('CFDecoder.decode_coords', sections=[
@@ -3568,8 +3568,14 @@ def from_dataset(cls, base, method='isel', default_slice=None,
             Index (e.g. 0 if `method` is 'isel') that shall be used for
             dimensions not covered by `dims` and `furtherdims`. If None, the
             whole slice will be used.
-        decoder: CFDecoder
-            The decoder that shall be used to decoder the `base` dataset
+        decoder: CFDecoder or dict
+            Arguments for the decoder. This can be one of
+
+            - an instance of :class:`CFDecoder`
+            - a subclass of :class:`CFDecoder`
+            - a dictionary with keyword-arguments to the automatically
+              determined decoder class
+            - None to automatically set the decoder
         squeeze: bool, optional
             Default True. If True, and the created arrays have a an axes with
             length 1, it is removed from the dimension list (e.g. an array
@@ -3634,12 +3640,17 @@ def ds2arr(arr):
             arr.attrs.update(attrs)
             return arr
 
-        if decoder is not None:
-            def get_decoder(arr):
-                return decoder
-        else:
-            def get_decoder(arr):
+        decoder_input = decoder
+
+        def get_decoder(arr):
+            if decoder_input is None:
                 return CFDecoder.get_decoder(base, arr)
+            elif isinstance(decoder_input, CFDecoder):
+                return decoder_input
+            elif isinstance(decoder_input, dict):
+                return CFDecoder.get_decoder(base, arr, **decoder_input)
+            else:
+                return decoder_input(base)
 
         def add_missing_dimensions(arr):
             # add the missing dimensions to the dataset. This is not anymore
@@ -3678,7 +3689,8 @@ def sel_method(key, dims, name=None):
                 ret = squeeze_array(arr.isel(**dims))
                 # delete the variable dimension for the idims
                 dims.pop('variable', None)
-                ret.psy.init_accessor(arr_name=key, base=base, idims=dims)
+                ret.psy.init_accessor(arr_name=key, base=base, idims=dims,
+                                      decoder=decoder)
                 return maybe_load(ret)
         else:
             def sel_method(key, dims, name=None):
@@ -3706,7 +3718,7 @@ def sel_method(key, dims, name=None):
                     ret = squeeze_array(arr.sel(**dims))
                 else:
                     ret = squeeze_array(arr.sel(method=method, **dims))
-                ret.psy.init_accessor(arr_name=key, base=base)
+                ret.psy.init_accessor(arr_name=key, base=base, decoder=decoder)
                 return maybe_load(ret)
         if 'name' not in kwargs:
             default_names = list(

diff --git a/tests/test_data.py b/tests/test_data.py
@@ -1144,6 +1144,34 @@ def test_from_dataset_12_list_and_2_vars(self):
         self.assertEqual(len(l[0]), 2)
         self.assertEqual(len(l[1]), 2)
 
+    def test_from_dataset_13_decoder_class(self):
+        ds = xr.Dataset(*self._from_dataset_test_variables)
+
+        class MyDecoder(psyd.CFDecoder):
+            pass
+
+        l = self.list_class.from_dataset(ds, name="v2", decoder=MyDecoder)
+        self.assertIsInstance(l[0].psy.decoder, MyDecoder)
+
+    def test_from_dataset_14_decoder_instance(self):
+        ds = xr.Dataset(*self._from_dataset_test_variables)
+
+        class MyDecoder(psyd.CFDecoder):
+            pass
+
+        decoder = MyDecoder(ds)
+
+        l = self.list_class.from_dataset(ds, name="v2", decoder=decoder)
+        self.assertIs(l[0].psy.decoder, decoder)
+
+    def test_from_dataset_15_decoder_kws(self):
+        ds = xr.Dataset(*self._from_dataset_test_variables)
+
+        l = self.list_class.from_dataset(ds, name="v2",
+                                         decoder=dict(x={'myx'}))
+        self.assertEqual(l[0].psy.decoder.x, {'myx'})
+
+
     def test_array_info(self):
         variables, coords = self._from_dataset_test_variables
         variables['v4'] = variables['v3'].copy()