feat: add function to deal with yearly based file names

pyspedas/omni/load.py

@@ -2,7 +2,7 @@
 import warnings
 import astropy
 
-from pyspedas.utilities.dailynames import dailynames
+from pyspedas.utilities.dailynames import dailynames, yearlynames
 from pyspedas.utilities.download import download
 from pytplot import time_clip as tclip
 from pytplot import cdf_to_tplot
@@ -31,16 +31,16 @@ def load(trange=['2013-11-5', '2013-11-6'],
 
     if 'min' in datatype:
         pathformat = level + '_' + datatype + '/%Y/omni_' + level + '_' + datatype + '_%Y%m01_v??.cdf'
+        remote_names = dailynames(file_format=pathformat, trange=trange, res=file_res)
     elif 'hour' in datatype:
         pathformat = 'hourly/%Y/omni2_h0_mrg1hr_%Y%m01_v??.cdf'
-        file_res = 24*3600*183.0  # 1 file every 6 months
         get_ignore_data = True  # required to load these files
+        remote_names = yearlynames(file_format=pathformat, trange=trange, resolution='half-year')
     else:
         logging.error('Invalid datatype: '+ datatype)
         return
 
     # find the full remote path names using the trange
-    remote_names = dailynames(file_format=pathformat, trange=trange, res=file_res)
 
     out_files = []
 

pyspedas/utilities/dailynames.py

@@ -84,3 +84,73 @@ def dailynames(directory='',
         files.append(directory + prefix + date + suffix)
 
     return files
+
+def yearlynames(
+    trange,
+    file_format="%Y%m%d",
+    resolution="year",
+    directory="",
+    prefix="",
+    suffix="",
+):
+    """
+    Creates a list of file names using a time range, resolution, and file format.
+
+    Parameters:
+        trange: list of str or list of datetime
+            Two-element list containing the start and end times for the file names.
+
+        resolution: str
+            Either 'year' or 'half-year' to determine the resolution.
+
+        file_format: str
+            Format of the file names using strftime directives.
+
+        directory: str
+            String containing the directory for the generated file names.
+
+        prefix: str
+            file name prefix.
+
+        suffix: str
+            file name suffix.
+
+    Returns:
+        List containing filenames.
+    """
+
+    if trange is None:
+        raise ValueError("No trange specified")
+
+    start_date = (
+        trange[0]
+        if isinstance(trange[0], datetime)
+        else datetime.strptime(trange[0], "%Y-%m-%d")
+    )
+    end_date = (
+        trange[1]
+        if isinstance(trange[1], datetime)
+        else datetime.strptime(trange[1], "%Y-%m-%d")
+    )
+
+    dates = []
+
+    if resolution == "half-year":
+        # Adjust the start date to be 6 months prior to the specified start date
+        if start_date.month <= 6:
+            adjusted_start_date = datetime(start_date.year - 1, start_date.month + 6, 1)
+        else:
+            adjusted_start_date = datetime(start_date.year, start_date.month - 6, 1)
+
+        # Generate all the January 1st and July 1st dates within the range
+        potential_dates = [datetime(year, month, 1) for year in range(start_date.year, end_date.year + 1) for month in [1, 7]]
+
+        # Filter out dates outside the range
+        dates = [date for date in potential_dates if adjusted_start_date < date <= end_date]
+    elif resolution == "year":
+        dates = [datetime(year, 1, 1) for year in range(start_date.year, end_date.year + 1)]
+    else:
+        raise ValueError("Invalid resolution specified. Choose 'year' or 'half-year'.")
+
+    files = [directory + prefix + date.strftime(file_format) + suffix for date in dates]
+    return files