Unify strftime/ptime notes and refactor code

Author: marat

Doc/library/datetime.rst

@@ -2762,17 +2762,16 @@ Notes:
    interchangeable.
 
 (9)
-   When used with the :meth:`~.datetime.strftime` method, the leading zero is optional
-   for formats ``%d``, ``%m``, ``%H``, ``%I``, ``%M``, ``%S``, ``%j``, ``%U``,
-   ``%W``, ``%V`` and ``%y`` (except that on Apple platforms, ``%y`` always produces
-   a leading zero). Use the ``%-`` flag to produce non-zero-padded output
-   (for example, ``%-d``).
-
-(10)
    When used with the :meth:`~.datetime.strptime` method, the leading zero is optional
    for  formats ``%d``, ``%m``, ``%H``, ``%I``, ``%M``, ``%S``, ``%j``, ``%U``,
    ``%W``, and ``%V``. Format ``%y`` does require a leading zero.
 
+   When used with the :meth:`~.datetime.strftime` method, the leading zero is optional
+   for formats ``%d``, ``%m``, ``%H``, ``%I``, ``%M``, ``%S``, ``%j``, ``%U``,
+   ``%W``, ``%V`` and ``%y``. The ``%-`` flag (for example, ``%-d``) will produce
+   non-zero-padded output, except for ``%-y`` on Apple platforms, which is still
+   zero-padded.
+
 (11)
    When parsing a month and day using :meth:`~.datetime.strptime`, always
    include a year in the format.  If the value you need to parse lacks a year,

Lib/_pydatetime.py

@@ -293,7 +293,7 @@ def _wrap_strftime(object, format, timetuple):
                     if i < n:
                         next_ch = format[i]
                         i += 1
-                        if sys.platform.startswith('win') or sys.platform.startswith('android'):
+                        if sys.platform in ['win32', 'android']:
                             push(_make_dash_replacement(next_ch, timetuple))
                         else:
                             push('%-' + next_ch)