擅长:python、mysql、java
<p>python3.8中的Walrus操作符<code>:=</code>是一个选项,或者您可以执行<code>for else</code>语句(注意<code>re.finditer</code>):</p>
<pre><code>import re
yyyyq_format = "19984"
for g in re.finditer("^(\d{4})(\d)$", yyyyq_format):
found_q = g[2]
break
else:
raise ValueError("Format \"yyyyq\" is not followed.")
print(found_q)
</code></pre>
<p>印刷品:</p>
<pre><code>4
</code></pre>