bpo-32337: Update documentats about dict order (GH-4973)
(cherry picked from commit dfbbbf16f9aab82330c634913441b5ac73267d9c)
Co-authored-by: hui shang <shangdahao@gmail.com>
diff --git a/Doc/tutorial/datastructures.rst b/Doc/tutorial/datastructures.rst
index b95aca8..7855ef2 100644
--- a/Doc/tutorial/datastructures.rst
+++ b/Doc/tutorial/datastructures.rst
@@ -497,7 +497,7 @@
assignments, slice assignments, or methods like :meth:`append` and
:meth:`extend`.
-It is best to think of a dictionary as an unordered set of *key: value* pairs,
+It is best to think of a dictionary as a set of *key: value* pairs,
with the requirement that the keys are unique (within one dictionary). A pair of
braces creates an empty dictionary: ``{}``. Placing a comma-separated list of
key:value pairs within the braces adds initial key:value pairs to the
@@ -509,9 +509,9 @@
value associated with that key is forgotten. It is an error to extract a value
using a non-existent key.
-Performing ``list(d.keys())`` on a dictionary returns a list of all the keys
-used in the dictionary, in arbitrary order (if you want it sorted, just use
-``sorted(d.keys())`` instead). [2]_ To check whether a single key is in the
+Performing ``list(d)`` on a dictionary returns a list of all the keys
+used in the dictionary, in insertion order (if you want it sorted, just use
+``sorted(d)`` instead). To check whether a single key is in the
dictionary, use the :keyword:`in` keyword.
Here is a small example using a dictionary::
@@ -519,16 +519,16 @@
>>> tel = {'jack': 4098, 'sape': 4139}
>>> tel['guido'] = 4127
>>> tel
- {'sape': 4139, 'guido': 4127, 'jack': 4098}
+ {'jack': 4098, 'sape': 4139, 'guido': 4127}
>>> tel['jack']
4098
>>> del tel['sape']
>>> tel['irv'] = 4127
>>> tel
- {'guido': 4127, 'irv': 4127, 'jack': 4098}
- >>> list(tel.keys())
- ['irv', 'guido', 'jack']
- >>> sorted(tel.keys())
+ {'jack': 4098, 'guido': 4127, 'irv': 4127}
+ >>> list(tel)
+ ['jack', 'guido', 'irv']
+ >>> sorted(tel)
['guido', 'irv', 'jack']
>>> 'guido' in tel
True
@@ -539,7 +539,7 @@
key-value pairs::
>>> dict([('sape', 4139), ('guido', 4127), ('jack', 4098)])
- {'sape': 4139, 'jack': 4098, 'guido': 4127}
+ {'sape': 4139, 'guido': 4127, 'jack': 4098}
In addition, dict comprehensions can be used to create dictionaries from
arbitrary key and value expressions::
@@ -551,7 +551,7 @@
keyword arguments::
>>> dict(sape=4139, guido=4127, jack=4098)
- {'sape': 4139, 'jack': 4098, 'guido': 4127}
+ {'sape': 4139, 'guido': 4127, 'jack': 4098}
.. _tut-loopidioms:
@@ -710,7 +710,3 @@
.. [1] Other languages may return the mutated object, which allows method
chaining, such as ``d->insert("a")->remove("b")->sort();``.
-
-.. [2] Calling ``d.keys()`` will return a :dfn:`dictionary view` object. It
- supports operations like membership test and iteration, but its contents
- are not independent of the original dictionary -- it is only a *view*.