* **Objects can be made [sortable](#sortable) with `'order=True'` and immutable with `'frozen=True'`.**
* **For object to be hashable, all attributes must be hashable and frozen must be True.**
* **For object to be [hashable](#hashable), all attributes must be hashable and frozen must be True.**
* **Function field() is needed because `'<attr_name>: list = []'` would make a list that is shared among all instances. Its 'default_factory' argument can be any [callable](#callable).**
* **For attributes of arbitrary type use `'typing.Any'`.**
@ -1055,6 +1055,13 @@ from dataclasses import make_dataclass
<li><strong>A function has it's default values evaluated when it's first encountered in the scope.</strong></li>
<li><strong>A function has its default values evaluated when it's first encountered in the scope.</strong></li>
<li><strong>Any changes to mutable objects will persist between invocations.</strong></li>
</ul>
<div><h2id="splatoperator"><ahref="#splatoperator"name="splatoperator">#</a>Splat Operator</h2><div><h3id="insidefunctioncall-1">Inside Function Call</h3><p><strong>Splat expands a collection into positional arguments, while splatty-splat expands a dictionary into keyword arguments.</strong></p><pre><codeclass="python language-python hljs">args = (<spanclass="hljs-number">1</span>, <spanclass="hljs-number">2</span>)
@ -886,7 +886,7 @@ Z = dataclasses.make_dataclass(<span class="hljs-string">'Z'</span>, [<span clas
<ul>
<li><strong>Objects can be made <ahref="#sortable">sortable</a> with <codeclass="python hljs"><spanclass="hljs-string">'order=True'</span></code> and immutable with <codeclass="python hljs"><spanclass="hljs-string">'frozen=True'</span></code>.</strong></li>
<li><strong>For object to be hashable, all attributes must be hashable and frozen must be True.</strong></li>
<li><strong>For object to be <ahref="#hashable">hashable</a>, all attributes must be hashable and frozen must be True.</strong></li>
<li><strong>Function field() is needed because <codeclass="python hljs"><spanclass="hljs-string">'<attr_name>: list = []'</span></code> would make a list that is shared among all instances. Its 'default_factory' argument can be any <ahref="#callable">callable</a>.</strong></li>
<li><strong>For attributes of arbitrary type use <codeclass="python hljs"><spanclass="hljs-string">'typing.Any'</span></code>.</strong></li>
</ul>
@ -895,6 +895,11 @@ Z = dataclasses.make_dataclass(<span class="hljs-string">'Z'</span>, [<span clas
<div><h4id="restoftypeannotationscpythoninterpreterignoresthemall">Rest of type annotations (CPython interpreter ignores them all):</h4><pre><codeclass="python language-python hljs"><spanclass="hljs-function"><spanclass="hljs-keyword">def</span><spanclass="hljs-title">func</span><spanclass="hljs-params">(<arg_name>: <type> [= <obj>])</span> -><type>:</span>
<div><h3id="slots">Slots</h3><p><strong>Mechanism that restricts objects to attributes listed in 'slots' and significantly reduces their memory footprint.</strong></p><pre><codeclass="python language-python hljs"><spanclass="hljs-class"><spanclass="hljs-keyword">class</span><spanclass="hljs-title">MyClassWithSlots</span>:</span>
'<strong>Adding <code class="python hljs"><span class="hljs-string">\'!r\'</span></code> before the colon converts object to string by calling its <a href="#class">repr()</a> method.</strong>':'<strong>Adding <code class="python hljs"><span class="hljs-string">\'!r\'</span></code> before the colon converts object to string by calling its repr() method (p. 14).</strong>',
'<strong>It can be any <a href="#callable">callable</a>, but is usually implemented as a function that returns a <a href="#closure">closure</a>.</strong>':'<strong>It can be any callable (p. 17), but is usually implemented as a function that returns a closure (p. 12).</strong>',
'<strong>Objects can be made <a href="#sortable">sortable</a> with <code class="python hljs"><span class="hljs-string">\'order=True\'</span></code> and immutable with <code class="python hljs"><span class="hljs-string">\'frozen=True\'</span></code>.</strong>':'<strong>Objects can be made sortable with <code class="python hljs"><span class="hljs-string">\'order=True\'</span></code> and immutable with <code class="python hljs"><span class="hljs-string">\'frozen=True\'</span></code>.</strong>',
'<strong>For object to be <a href="#hashable">hashable</a>, all attributes must be hashable and frozen must be True.</strong>':'<strong>For object to be hashable, all attributes must be hashable and frozen must be True.</strong>',
'<strong>Function field() is needed because <code class="python hljs"><span class="hljs-string">\'<attr_name>: list = []\'</span></code> would make a list that is shared among all instances. Its \'default_factory\' argument can be any <a href="#callable">callable</a>.</strong>':'<strong>Function field() is needed because <code class="python hljs"><span class="hljs-string">\'<attr_name>: list = []\'</span></code> would make a list that is shared among all instances. Its \'default_factory\' argument can be any callable (p. 17).</strong>',
'<strong>Sequence iterators returned by the <a href="#iterator">iter()</a> function, such as list_iterator and set_iterator.</strong>':'<strong>Sequence iterators returned by the iter() function, such as list_iterator and set_iterator (p. 3).</strong>',
'<strong>Objects returned by the <a href="#itertools">itertools</a> module, such as count, repeat and cycle.</strong>':'<strong>Objects returned by the itertools module, such as count, repeat and cycle (p. 3).</strong>',
Jure Šorn
3 years ago