Minor bug fixes and new tests

gempakio/decode/gempak.py

@@ -900,7 +900,9 @@ def gdxarray(self, parameter=None, date_time=None, coordinate=None,
 
         date_time2 : datetime or array-like of datetime
             Secondary valid datetime of the grid. Alternatively
-            can be a string with the format YYYYmmddHHMM.
+            a string with the format YYYYmmddHHMM or first|FIRST
+            or last|LAST which function to retrieve the latest
+            and oldest time within the file, respectively.
 
         level2: float or array_like of float
             Secondary vertical level. Typically used for layers.
@@ -947,11 +949,13 @@ def gdxarray(self, parameter=None, date_time=None, coordinate=None,
 
         if date_time2 is not None:
             if (not isinstance(date_time2, Iterable)
-               or isinstance(date_time2, str)):
+               or (isinstance(date_time2, str)
+               and date_time2 not in ['first', 'FIRST', 'last', 'LAST'])):
                 date_time2 = [date_time2]
-            for i, dt in enumerate(date_time2):
-                if isinstance(dt, str):
-                    date_time2[i] = datetime.strptime(dt, '%Y%m%d%H%M')
+            if date_time2 not in ['first', 'FIRST', 'last', 'LAST']:
+                for i, dt in enumerate(date_time2):
+                    if isinstance(dt, str):
+                        date_time2[i] = datetime.strptime(dt, '%Y%m%d%H%M')
 
         if level2 is not None and not isinstance(level2, Iterable):
             level2 = [level2]
@@ -962,9 +966,14 @@ def gdxarray(self, parameter=None, date_time=None, coordinate=None,
         # Do this now or the matched filter iterator will be consumed
         # prematurely.
         if date_time in ['last', 'LAST']:
-            date_time = [max((d.DATTIM for d in matched))]
+            date_time = [max((d.DATTIM1 for d in matched))]
         elif date_time in ['first', 'FIRST']:
-            date_time = [min((d.DATTIM for d in matched))]
+            date_time = [min((d.DATTIM1 for d in matched))]
+
+        if date_time2 in ['last', 'LAST']:
+            date_time2 = [max((d.DATTIM2 for d in matched))]
+        elif date_time2 in ['first', 'FIRST']:
+            date_time2 = [min((d.DATTIM2 for d in matched))]
 
         if parameter is not None:
             matched = filter(
@@ -2052,7 +2061,7 @@ def snxarray(self, station_id=None, station_number=None,
             if 'TXPB' in snd:
                 wmo_text['txpb'] = snd.pop('TXPB')
             if wmo_text:
-                attrs['WMO_CODES'] = wmo_text
+                attrs['wmo_codes'] = wmo_text
 
             dt = datetime.combine(snd.pop('DATE'), snd.pop('TIME'))
             if vcoord == 'pres':

setup.py

@@ -6,7 +6,7 @@
 from setuptools import find_packages, setup
 
 NAME = 'gempakio'
-VERSION = '0.8.0'
+VERSION = '0.8.1'
 DESCR = 'Read GEMPAK data with pure Python.'
 URL = 'https://github.com/nawendt/gempakio'
 REQUIRES = ['pyproj', 'xarray']

tests/test_grids.py

@@ -4,6 +4,7 @@
 """Tests for decoding GEMPAK grid files."""
 
 
+from datetime import datetime, timedelta
 from pathlib import Path
 
 import numpy as np
@@ -24,3 +25,19 @@ def test_grid_loading(grid_name):
     gempak = np.load(d)['values']
 
     np.testing.assert_allclose(gio, gempak, rtol=1e-6, atol=0)
+
+
+@pytest.mark.parametrize('keyword,date_time', [
+    ('FIRST', '201204141200'), ('LAST', '201204150000')
+])
+def test_time_keywords(keyword, date_time):
+    """Test time keywords FIRST and LAST."""
+    g = Path(__file__).parent / 'data' / 'multi_date.grd'
+
+    grid = GempakGrid(g).gdxarray(date_time=keyword)[0]
+    dt64 = grid.time.values[0]
+    epoch_seconds = int(dt64) / 1e9
+    grid_dt = datetime(1970, 1, 1) + timedelta(seconds=epoch_seconds)
+    expected = datetime.strptime(date_time, '%Y%m%d%H%M')
+
+    assert grid_dt == expected

tests/test_soundings.py

@@ -3,6 +3,7 @@
 # SPDX-License-Identifier: BSD-3-Clause
 """Tests for decoding GEMPAK grid files."""
 
+from datetime import datetime, timedelta
 from pathlib import Path
 
 import numpy as np
@@ -84,7 +85,7 @@ def test_sounding_text(text_type):
     gso = GempakSounding(g).snxarray(station_id='OUN')[0]
     gempak = pd.read_csv(d)
 
-    text = gso.attrs['WMO_CODES'][text_type]
+    text = gso.attrs['wmo_codes'][text_type]
     gem_text = gempak.loc[:, text_type.upper()][0]
 
     assert text == gem_text
@@ -157,3 +158,19 @@ def test_unmerged_sigw_pressure_sounding():
     np.testing.assert_allclose(gdrct, ddrct, rtol=1e-10, atol=1e-2)
     np.testing.assert_allclose(gsped, dsped, rtol=1e-10, atol=1e-2)
     np.testing.assert_allclose(ghght, dhght, rtol=1e-10, atol=1e-1)
+
+
+@pytest.mark.parametrize('keyword,date_time', [
+    ('FIRST', '202011070000'), ('LAST', '202011070100')
+])
+def test_time_keywords(keyword, date_time):
+    """Test time keywords FIRST and LAST."""
+    g = Path(__file__).parent / 'data' / 'unmerged_with_text.snd'
+
+    gso = GempakSounding(g).snxarray(date_time=keyword)[0]
+    expected = datetime.strptime(date_time, '%Y%m%d%H%M')
+    dt64 = gso.time.values[0]
+    epoch_seconds = int(dt64) / 1e9
+    sounding_dt = datetime(1970, 1, 1) + timedelta(seconds=epoch_seconds)
+
+    assert sounding_dt == expected

tests/test_surface.py

@@ -111,3 +111,17 @@ def test_multiple_special_observations():
 
     assert date_time == datetime(2021, 9, 7, 16, 4)
     assert text == gem_text
+
+
+@pytest.mark.parametrize('keyword,date_time', [
+    ('FIRST', '202109062353'), ('LAST', '202109071604')
+])
+def test_time_keywords(keyword, date_time):
+    """Test time keywords FIRST and LAST."""
+    g = Path(__file__).parent / 'data' / 'msn_std_sfc.sfc'
+
+    gsf = GempakSurface(g).sfjson(date_time=keyword)[-1]
+    expected = datetime.strptime(date_time, '%Y%m%d%H%M')
+    surface_dt = gsf['properties']['date_time']
+
+    assert surface_dt == expected