Comment

Author: toobaz

pandas/core/dtypes/concat.py

@@ -565,6 +565,11 @@ def convert_sparse(x, axis):
 
 
 def _concat_indexes_same_dtype_rangeindex(indexes):
+    # Concatenates multiple RangeIndex instances. All members of "indexes" must
+    # be of type RangeIndex; result will be RangeIndex if possible, Int64Index
+    # otherwise. E.g.:
+    # indexes = [RangeIndex(3), RangeIndex(3, 6)] -> RangeIndex(6)
+    # indexes = [RangeIndex(3), RangeIndex(4, 6)] -> Int64Index([0,1,2,4,5])
 
     start = step = next = None