From 44c1cdd53f5f782e7b0d0603a530ba331fa35b94 Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Sun, 5 Apr 2020 02:57:05 -0700 Subject: [PATCH] Fix misinformation about NaN != NaN comparison (GH-19357) (GH-19384) (cherry picked from commit 810f68f1282c917fc1ad6af540a9f08524dfe310) Co-authored-by: Mark Dickinson --- Doc/reference/expressions.rst | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst index 51e779c0536..3c14fc98d00 100644 --- 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