擅长:python、mysql、java
<p>为了执行如此复杂的操作,我们可以将其分解为更简单的操作。在最简单的层次上,我们希望用另一个字符串替换短划线(-):</p>
<pre><code>>>> x = 'corgi'
>>> y = 'BLANK 1'
>>> x if x != '-' else y
corgi
>>> x = '-'
>>> y = 'BLANK 2'
>>> x if x != '-' else y
BLANK 2
</code></pre>
<p>下一步是将<code>["corgi",'-',"labrador"]</code>替换为<code>["corgi",'BLANK 2',"labrador"]</code>:</p>
^{pr2}$
<p>最后,我们来看看全局:</p>
<pre><code>>>> C = [ [animal,
[x if x != '-' else y for x, y in zip(breed, B)] ]
for animal, breed in A]
>>> print C
[['dog', ['corgi', 'BLANK 2', 'labrador']], ['cat', ['tabby', 'persian', 'BLANK 3']]]
</code></pre>