擅长:python、mysql、java
<p>你可以试试这个:</p>
<pre><code>list=[["Hello", "mY", "WORLD"], ["MY", "yOur", "ouRS"]]
new_list = [ [ i.lower() for i in innerlist ] for innerlist in list]
print(new_list)
</code></pre>
<p>输出:</p>
<pre><code>[['hello', 'my', 'world'], ['my', 'your', 'ours']]
</code></pre>