Added a note in each regarding the fact that unicode strings that look the same
may not compare equal (due to the possibility of multiple representations).
diff --git a/Doc/library/unicodedata.rst b/Doc/library/unicodedata.rst
index 017d4ee..ec788c5 100644
--- a/Doc/library/unicodedata.rst
+++ b/Doc/library/unicodedata.rst
@@ -107,7 +107,7 @@
based on the definition of canonical equivalence and compatibility equivalence.
In Unicode, several characters can be expressed in various way. For example, the
character U+00C7 (LATIN CAPITAL LETTER C WITH CEDILLA) can also be expressed as
- the sequence U+0043 (LATIN CAPITAL LETTER C) U+0327 (COMBINING CEDILLA).
+ the sequence U+0327 (COMBINING CEDILLA) U+0043 (LATIN CAPITAL LETTER C).
For each character, there are two normal forms: normal form C and normal form D.
Normal form D (NFD) is also known as canonical decomposition, and translates
@@ -126,6 +126,10 @@
(NFKC) first applies the compatibility decomposition, followed by the canonical
composition.
+ Even if two unicode strings are normalized and look the same to
+ a human reader, if one has combining characters and the other
+ doesn't, they may not compare equal.
+
.. versionadded:: 2.3
In addition, the module exposes the following constant:
diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst
index 3364fd6..a1c4185 100644
--- a/Doc/reference/expressions.rst
+++ b/Doc/reference/expressions.rst
@@ -1040,7 +1040,7 @@
* Strings are compared lexicographically using the numeric equivalents (the
result of the built-in function :func:`ord`) of their characters. Unicode and
- 8-bit strings are fully interoperable in this behavior.
+ 8-bit strings are fully interoperable in this behavior. [#]_
* Tuples and lists are compared lexicographically using comparison of
corresponding elements. This means that to compare equal, each element must
@@ -1328,6 +1328,12 @@
cases, Python returns the latter result, in order to preserve that
``divmod(x,y)[0] * y + x % y`` be very close to ``x``.
+.. [#] While comparisons between unicode strings make sense at the byte
+ level, they may be counter-intuitive to users. For example, the
+ strings ``u"\u00C7"`` and ``u"\u0327\u0043"`` compare differently,
+ even though they both represent the same unicode character (LATIN
+ CAPTITAL LETTER C WITH CEDILLA).
+
.. [#] The implementation computes this efficiently, without constructing lists or
sorting.