update

ecml_tools/data.py

@@ -5,21 +5,84 @@
 # granted to it by virtue of its status as an intergovernmental organisation
 # nor does it submit to any jurisdiction.
 
+import os
+import re
+from functools import cached_property
+
+import yaml
 import zarr
 
+# Question: should properties be cached?
+
+
+class Base:
+    def subset(self, **kwargs):
+        if not kwargs:
+            return self
+
+        if "frequency" in kwargs:
+            frequency = kwargs.pop("frequency")
+
+            return Subset(self, self.frequency_to_indices(frequency)).subset(**kwargs)
+
+        if "start" in kwargs or "end" in kwargs:
+            start = kwargs.pop("start")
+            end = kwargs.pop("end")
+
+            def is_year(x):
+                return isinstance(x, int) and 1000 <= x <= 9999
+
+            if start is None or is_year(start):
+                if end is None or is_year(end):
+                    return Subset(self, self.years_to_indices(start, end)).subset(
+                        **kwargs
+                    )
+
+            raise NotImplementedError(f"Unsupported start/end: {start} {end}")
+
+        raise NotImplementedError("Unsupported arguments: " + ", ".join(kwargs))
+
+    def frequency_to_indices(self, frequency):
+        requested_frequency = _frequency_to_hours(frequency)
+        delta = self.dates[1] - self.dates[0]
+        dataset_frequency = delta.item().total_seconds() / 3600
+        assert dataset_frequency.is_integer()
+        dataset_frequency = int(dataset_frequency)
+        assert requested_frequency % dataset_frequency == 0
+        # Question: where do we start? first date, or first date that is a multiple of the frequency?
+        step = requested_frequency // dataset_frequency
+
+        return range(0, len(self), step)
+
+    def years_to_indices(self, start, end):
+        # TODO: optimize
+        start = self.dates[0].year if start is None else start
+        end = self.dates[-1].year if end is None else end
 
-class Dataset:
+        return [i for i, date in enumerate(self.dates) if start <= date.year <= end]
+
+
+class Dataset(Base):
     def __init__(self, path):
-        self.z = zarr.open(path)
+        print(path)
+        self.z = zarr.convenience.open(path, "r")
 
     def __len__(self):
         return self.z.data.shape[0]
 
     def __getitem__(self, n):
         return self.z.data[n]
 
+    @property
+    def shape(self):
+        return self.z.data.shape
+
+    @cached_property
+    def dates(self):
+        return self.z.dates[:]  # Convert to numpy
+
 
-class Concat:
+class Concat(Base):
     def __init__(self, *datasets):
         self.datasets = list(datasets)
 
@@ -37,7 +100,7 @@ def __getitem__(self, n):
         return self.datasets[k][n]
 
 
-class Subset:
+class Subset(Base):
     def __init__(self, dataset, indices):
         self.dataset = dataset
         self.indices = list(indices)
@@ -49,16 +112,46 @@ def __getitem__(self, n):
     def __len__(self):
         return len(self.indices)
 
+    @cached_property
+    def shape(self):
+        return (len(self),) + self.dataset.shape[1:]
+
+    @cached_property
+    def dates(self):
+        return self.dataset.dates[self.indices]
+
 
 def name_to_path(name):
     if name.endswith(".zarr"):
         return name
-    # open("~/.ecml-tools")
 
-    return name
+    with open(os.path.expanduser("~/.ecml-tools")) as f:
+        config = yaml.safe_load(f)
+
+    return os.path.join(config["zarr_root"], name + ".zarr")
+
+
+def _frequency_to_hours(frequency):
+    if isinstance(frequency, int):
+        return frequency
+
+    m = re.match(r"(\d+)([dh])?", frequency)
+    if m is None:
+        raise ValueError("Invalid frequency: " + frequency)
+
+    frequency = int(m.group(1))
+    if m.group(2) == "h":
+        return frequency
+
+    if m.group(2) == "d":
+        return frequency * 24
+
+    raise NotImplementedError()
 
 
 def open_dataset(*args, **kwargs):
     paths = [name_to_path(name) for name in args]
-    assert len(paths) == 1
-    return Dataset(paths[0])
+    assert len(paths) >= 1
+    if len(paths) > 2:
+        return Concat([Dataset(path) for path in paths]).subset(**kwargs)
+    return Dataset(paths[0]).subset(**kwargs)

setup.py

@@ -43,6 +43,8 @@ def read(fname):
     include_package_data=True,
     install_requires=[
         "zarr",
+        "pyyaml",
+        "numpy",
     ],
     extras_require={},
     zip_safe=True,