fixup: define itertools.pairwise for python < 3.10

searvey/ioc.py

@@ -16,7 +16,6 @@
 import collections
 import functools
 import io
-import itertools
 import logging
 import typing as T
 import warnings
@@ -48,6 +47,7 @@
 from .utils import get_region
 from .utils import merge_datasets
 from .utils import NOW
+from .utils import pairwise
 from .utils import resolve_timestamp
 
 
@@ -498,7 +498,7 @@ def _generate_urls(
     periods = duration.days // 30 + 2
     urls = []
     date_range = pd.date_range(start_date, end_date, periods=periods, unit="us", inclusive="both")
-    for start, stop in itertools.pairwise(date_range):
+    for start, stop in pairwise(date_range):
         timestart = _ioc_date(start)
         timestop = _ioc_date(stop)
         url = BASE_URL.format(ioc_code=station_id, timestart=timestart, timestop=timestop)

searvey/utils.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import itertools
+import typing as T
 from typing import Dict
 from typing import Final
 from typing import Iterable
@@ -25,11 +26,20 @@
 
 NOW: Final = "now"
 
+try:
+    from itertools import pairwise
+except ImportError:
+
+    def pairwise(iterable: T.Iterable[_T]) -> T.Iterator[tuple[_T, _T]]:
+        # pairwise('ABCDEFG') --> AB BC CD DE EF FG
+        a, b = itertools.tee(iterable)
+        next(b, None)
+        return zip(a, b)
+
+
 # https://gis.stackexchange.com/questions/201789/verifying-formula-that-will-convert-longitude-0-360-to-180-to-180
 # lon1 is the longitude varying from -180 to 180 or 180W-180E
 # lon3 is the longitude variable from 0 to 360 (all positive)
-
-
 def lon1_to_lon3(lon1: ScalarOrArray) -> ScalarOrArray:
     return lon1 % 360