Elaborate on join_asof description

judahrand · judahrand · commit e6da4df5cae7 · 2024-03-04T10:23:28.000Z
These descriptions are mostly lifted from the Pandas `merge_asof` docs. https://pandas.pydata.org/docs/reference/api/pandas.merge_asof.html#pandas.merge_asof
diff --git a/python/pyarrow/_dataset.pyx b/python/pyarrow/_dataset.pyx
@@ -884,6 +884,12 @@ cdef class Dataset(_Weakrefable):
         """
         Perform an asof join between this dataset and another one.
 
+        This is similar to a left-join except that we match on nearest key rather
+        than equal keys. Both datasets must be sorted by the key. This type of join
+        is most useful for time series data that are not perfectly aligned.
+
+        Optionally match on equivalent keys with "by" before searching with "on".
+
         Result of the join will be a new Dataset, where further
         operations can be applied.
 
diff --git a/python/pyarrow/table.pxi b/python/pyarrow/table.pxi
@@ -4863,6 +4863,12 @@ cdef class Table(_Tabular):
         """
         Perform an asof join between this table and another one.
 
+        This is similar to a left-join except that we match on nearest key rather
+        than equal keys. Both tables must be sorted by the key. This type of join
+        is most useful for time series data that are not perfectly aligned.
+
+        Optionally match on equivalent keys with "by" before searching with "on".
+
         Result of the join will be a new Table, where further
         operations can be applied.
 
