擅长:python、mysql、java
<p>它是一个<code>list comprehension</code>如果您展开,它将如下所示-></p>
<pre><code>result = []
for i in s: # will fetch element one by one from iterable
if i.isalnum() or i=="_": # checking condition
result.append(i) # if true, then append it to the list
</code></pre>
<p>上述代码可重写为-</p>
<pre><code>result = [i for i in s if i.isalnum() or i=="_"]
</code></pre>