bpo-32337: Update documentats about dict order (GH-4973)

(cherry picked from commit dfbbbf1)

Co-authored-by: hui shang <[email protected]>

Author: miss-islington

Doc/library/stdtypes.rst

@@ -4256,17 +4256,17 @@ support membership tests:
    Return an iterator over the keys, values or items (represented as tuples of
    ``(key, value)``) in the dictionary.
 
-   Keys and values are iterated over in an arbitrary order which is non-random,
-   varies across Python implementations, and depends on the dictionary's history
-   of insertions and deletions. If keys, values and items views are iterated
-   over with no intervening modifications to the dictionary, the order of items
-   will directly correspond.  This allows the creation of ``(value, key)`` pairs
+   Keys and values are iterated over in insertion order.
+   This allows the creation of ``(value, key)`` pairs
    using :func:`zip`: ``pairs = zip(d.values(), d.keys())``.  Another way to
    create the same list is ``pairs = [(v, k) for (k, v) in d.items()]``.
 
    Iterating views while adding or deleting entries in the dictionary may raise
    a :exc:`RuntimeError` or fail to iterate over all entries.
 
+   .. versionchanged:: 3.7
+      Dict order is guaranteed to be insertion order.
+
 .. describe:: x in dictview
 
    Return ``True`` if *x* is in the underlying dictionary's keys, values or
@@ -4293,17 +4293,17 @@ An example of dictionary view usage::
    >>> print(n)
    504
 
-   >>> # keys and values are iterated over in the same order
+   >>> # keys and values are iterated over in the same order (insertion order)
    >>> list(keys)
-   ['eggs', 'bacon', 'sausage', 'spam']
+   ['eggs', 'sausage', 'bacon', 'spam']
    >>> list(values)
    [2, 1, 1, 500]
 
    >>> # view objects are dynamic and reflect dict changes
    >>> del dishes['eggs']
    >>> del dishes['sausage']
    >>> list(keys)
-   ['spam', 'bacon']
+   ['bacon', 'spam']
 
    >>> # set operations
    >>> keys & {'eggs', 'bacon', 'salad'}

Doc/tutorial/datastructures.rst

@@ -497,7 +497,7 @@ You can't use lists as keys, since lists can be modified in place using index
 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
@@ -509,26 +509,26 @@ pair with ``del``. If you store using a key that is already in use, the old
 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::
 
    >>> 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 @@ The :func:`dict` constructor builds dictionaries directly from sequences of
 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 @@ When the keys are simple strings, it is sometimes easier to specify pairs using
 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 @@ interpreter will raise a :exc:`TypeError` exception.
 
 .. [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*.

Misc/ACKS

@@ -1449,6 +1449,7 @@ Ian Seyer
 Dmitry Shachnev
 Anish Shah
 Daniel Shahaf
+Hui Shang
 Mark Shannon
 Ha Shao
 Richard Shapiro

Misc/NEWS.d/next/Documentation/2017-12-22-17-29-37.bpo-32337.eZe-ID.rst

@@ -0,0 +1 @@
+Update documentation related with ``dict`` order.