Merge pull request #27 from ScottWales/groupbystr

Allow pandas periods for blocked_resample

Author: Scott Wales

setup.cfg

@@ -14,7 +14,7 @@ source =
 [tool:pytest]
 addopts = --doctest-modules --doctest-glob="*.rst"
 doctest_optionflags=ELLIPSIS
-norecursedirs = benchmark notebooks
+norecursedirs = benchmarks notebooks .asv
 
 [mypy]
 files = src/climtas,test

src/climtas/blocked.py

@@ -137,6 +137,10 @@ def resample_op(block, op, axis, count):
                 v = v[:: self.count]
             result.coords[k] = v
 
+        # Set after we create 'result' - if the original name is None it will
+        # be replaced by the dask name, so results won't be identical to xarray
+        result.name = self.da.name
+
         return result
 
     def mean(self) -> xarray.DataArray:
@@ -170,21 +174,47 @@ def blocked_resample(da: xarray.DataArray, indexer=None, **kwargs) -> BlockedRes
     >>> time = pandas.date_range('20010101','20010110', freq='H', closed='left')
     >>> hourly = xarray.DataArray(numpy.random.random(time.size), coords=[('time', time)])
 
+    >>> blocked_daily_max = blocked_resample(hourly, time='1D').max()
+    >>> xarray_daily_max = hourly.resample(time='1D').max()
+    >>> xarray.testing.assert_identical(blocked_daily_max, xarray_daily_max)
+
     >>> blocked_daily_max = blocked_resample(hourly, time=24).max()
     >>> xarray_daily_max = hourly.resample(time='1D').max()
-    >>> xarray.testing.assert_equal(blocked_daily_max, xarray_daily_max)
+    >>> xarray.testing.assert_identical(blocked_daily_max, xarray_daily_max)
 
     Args:
         da (:class:`xarray.DataArray`): Resample target
-        indexer/kwargs (Dict[dim, count]): Mapping of dimension name to count along that axis
+        indexer/kwargs (Dict[dim, count]): Mapping of dimension name to count
+            along that axis. May be an integer or a time interval understood by
+            pandas (that interval must evenly divide the dataset).
 
     Returns:
         :class:`BlockedResampler`
     """
     if indexer is None:
         indexer = kwargs
-    assert len(indexer) == 1
+    else:
+        indexer = {**indexer, **kwargs}
+
+    if len(indexer) != 1:
+        raise Exception(
+            f"Only one dimension can be resampled at a time, received {indexer}"
+        )
+
     dim, count = list(indexer.items())[0]
+
+    if not isinstance(count, int):
+        # Something like a pandas period, resample the time axis to get the count
+        counts = da[dim].resample({dim: count}).count()
+        if counts.min() != counts.max():
+            raise Exception(
+                f"Period '{count}' does not evenly divide dimension '{dim}'"
+            )
+        count = counts.values[0]
+
+    if da.sizes[dim] % count != 0:
+        raise Exception(f"Period '{count}' does not evenly divide dimension '{dim}'")
+
     return BlockedResampler(da, dim=dim, count=count)
 
 

test/test_blocked.py

@@ -38,6 +38,22 @@ def sample(request):
     return samples[request.param]
 
 
+@pytest.fixture(params=["daily", "daily_dask"])
+def sample_hr(request):
+    time = pandas.date_range("20020101", "20050101", freq="H", closed="left")
+
+    samples = {
+        "daily": xarray.DataArray(
+            numpy.random.random(time.size), coords=[("time", time)]
+        ),
+        "daily_dask": xarray.DataArray(
+            dask.array.random.random(time.size), coords=[("time", time)]
+        ),
+    }
+
+    return samples[request.param]
+
+
 def test_groupby_dayofyear(sample):
     time = pandas.date_range("20020101", "20050101", freq="D", closed="left")
     daily = xarray.DataArray(numpy.random.random(time.size), coords=[("time", time)])
@@ -171,6 +187,20 @@ def test_resample_safety(sample):
         blocked_resample(sliced, time=24)
 
 
+def test_resample(sample_hr):
+    expected = sample_hr.resample(time="D").mean()
+
+    result = blocked_resample(sample_hr, time=24).mean()
+    xarray.testing.assert_equal(expected, result)
+    xarray.testing.assert_identical(expected, result)
+
+    result = blocked_resample(sample_hr, time="D").mean()
+    xarray.testing.assert_identical(expected, result)
+
+    result = blocked_resample(sample_hr, {"time": "D"}).mean()
+    xarray.testing.assert_identical(expected, result)
+
+
 def test_groupby_safety(sample):
     # Not a coordinate
     sliced = sample