擅长:python、mysql、java
<p>您可以简单地执行以下操作:</p>
<pre><code>import re
with open('a.txt','r') as f:
text_value = f.read()
sum_val = sum(map(int, re.findall(r'<sum>(\d+)</sum>', text_value)))
with open('a.txt','w') as f:
f.write(re.sub(r'<CtrlSum>(.+)</CtrlSum>', f'<CtrlSum>{sum_val}</CtrlSum>', text_value))
</code></pre>
<p>不需要<code>readlines()</code>或<code>writelines()</code>或任何循环。只需用<code>.read()</code>->;处理it-><code>write()</code></p>