Merged revisions 83277 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/branches/py3k

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  r83277 | mark.dickinson | 2010-07-30 14:13:02 +0100 (Fri, 30 Jul 2010) | 1 line

  Add note about surprising behaviour from round function.
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diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 5160e08544d1f6fea64011153ab86c5b3a1d21a0..a2877320825fbab7761c0d04253ce98d806ae7f3 100644 (file)
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -961,6 +961,13 @@ are always available.  They are listed here in alphabetical order.
    The return value is an integer if called with one argument, otherwise of the
    same type as *x*.
 
+   .. note::
+
+      The behavior of :func:`round` for floats can be surprising: for example,
+      ``round(2.675, 2)`` gives ``2.67`` instead of the expected ``2.68``.
+      This is not a bug: it's a result of the fact that most decimal fractions
+      can't be represented exactly as a float.  See :ref:`tut-fp-issues` for
+      more information.
 
 .. function:: set([iterable])
    :noindex: