Fix misinformation about NaN != NaN comparison (GH-19357) (GH-19384)

(cherry picked from commit 810f68f1282c917fc1ad6af540a9f08524dfe310)

Co-authored-by: Mark Dickinson <mdickinson@enthought.com>

diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst
index 51e779c053688704e3a335fa4b3bdaee41b581eb..3c14fc98d008024193c7f43e8043e3c95ea870eb 100644 (file)
--- a/Doc/reference/expressions.rst
+++ b/Doc/reference/expressions.rst
@@ -1420,8 +1420,9 @@ built-in types.
   The not-a-number values ``float('NaN')`` and ``decimal.Decimal('NaN')`` are
   special.  Any ordered comparison of a number to a not-a-number value is false.
   A counter-intuitive implication is that not-a-number values are not equal to
-  themselves.  For example, if ``x = float('NaN')``, ``3 < x``, ``x < 3``, ``x
-  == x``, ``x != x`` are all false.  This behavior is compliant with IEEE 754.
+  themselves.  For example, if ``x = float('NaN')``, ``3 < x``, ``x < 3`` and
+  ``x == x`` are all false, while ``x != x`` is true.  This behavior is
+  compliant with IEEE 754.
 
 * Binary sequences (instances of :class:`bytes` or :class:`bytearray`) can be
   compared within and across their types.  They compare lexicographically using