擅长:python、mysql、java
<p>在python-dev邮件列表中给出的赋值表达式中不允许更复杂的赋值,这是有道理的</p>
<p>特别是Chris Angelico:</p>
<blockquote>
<p>Assignment to arbitrary targets
would also mean permitting iterable unpacking, which is not desired
("x, y := 3, 4"??), and there weren't enough use-cases for
attribute/item assignment to justify creating a rule of "you can
assign to any single target, but can't unpack". In the future, if such
use-cases are found, the grammar can be expanded.</p>
</blockquote>
<p><a href="https://mail.python.org/pipermail/python-dev/2018-July/154628.html" rel="nofollow noreferrer">https://mail.python.org/pipermail/python-dev/2018-July/154628.html</a></p>
<p>来自圭多本人:</p>
<blockquote>
<p>Also nobody had a use case.</p>
</blockquote>
<p><a href="https://mail.python.org/pipermail/python-dev/2018-July/154631.html" rel="nofollow noreferrer">https://mail.python.org/pipermail/python-dev/2018-July/154631.html</a></p>
<p>这可能是一个尽可能接近的解释。据推测,如果有需求,该功能可能会在未来的某个版本中扩展</p>