ENH: improve add_newdocs performance

replace slow exec with a direct __import__.
improves `import numpy` speed by about 10%.

1 files changed, 4 insertions, 5 deletions

diff --git a/numpy/lib/function_base.py b/numpy/lib/function_base.py
index a70f74f60..9176d9950 100644
--- a/numpy/lib/function_base.py
+++ b/numpy/lib/function_base.py
@@ -3110,15 +3110,14 @@ def add_newdoc(place, obj, doc):
     that the docstrings were changed.
        """
     try:
-        new = {}
-        exec('from %s import %s' % (place, obj), new)
+        new = getattr(__import__(place, globals(), {}, [obj]), obj)
         if isinstance(doc, str):
-            add_docstring(new[obj], doc.strip())
+            add_docstring(new, doc.strip())
         elif isinstance(doc, tuple):
-            add_docstring(getattr(new[obj], doc[0]), doc[1].strip())
+            add_docstring(getattr(new, doc[0]), doc[1].strip())
         elif isinstance(doc, list):
             for val in doc:
-                add_docstring(getattr(new[obj], val[0]), val[1].strip())
+                add_docstring(getattr(new, val[0]), val[1].strip())
     except:
         pass