Commits

Armin Rigo committed 5c7fa43

Document __len__/__length_hint__.

Comments (0)

Files changed (1)

pypy/doc/cpython_differences.rst

   type and vice versa. For builtin types, a dictionary will be returned that
   cannot be changed (but still looks and behaves like a normal dictionary).
 
+* the ``__len__`` or ``__length_hint__`` special methods are sometimes
+  called by CPython to get a length estimate to preallocate internal arrays.
+  So far, PyPy never calls ``__len__`` for this purpose, and never calls
+  ``__length_hint__`` at all.
+
 
 .. include:: _ref.txt