REF/CLN (feedback): remove min_count arg from libgroupby.group_nth

Author: arw2019

pandas/_libs/groupby.pyx

@@ -986,8 +986,8 @@ def group_last(rank_t[:, :] out,
 def group_nth(rank_t[:, :] out,
               int64_t[:] counts,
               ndarray[rank_t, ndim=2] values,
-              const int64_t[:] labels, int64_t rank=1,
-              Py_ssize_t min_count=-1):
+              const int64_t[:] labels, int64_t rank=1
+              ):
     """
     Only aggregates on axis=0
     """
@@ -997,6 +997,7 @@ def group_nth(rank_t[:, :] out,
         ndarray[rank_t, ndim=2] resx
         ndarray[int64_t, ndim=2] nobs
         bint runtime_error = False
+        Py_ssize_t min_count = -1
 
     assert min_count == -1, "'min_count' only used in add and prod"
 

pandas/core/groupby/ops.py

@@ -603,7 +603,7 @@ def _aggregate(
     ):
         if agg_func is libgroupby.group_nth:
             # different signature from the others
-            agg_func(result, counts, values, comp_ids, rank=1, min_count=min_count)
+            agg_func(result, counts, values, comp_ids, rank=1)
         else:
             agg_func(result, counts, values, comp_ids, min_count)