擅长:python、mysql、java
<p>注意<a href="https://pandas.pydata.org/pandas-docs/stable/whatsnew/v0.23.0.html#dataframe-astype-performs-column-wise-conversion-to-categorical" rel="nofollow noreferrer">since pandas 0.23.0</a>您不再<code>apply</code>将多个列转换为分类数据类型。现在您只需执行<code>df[to_convert].astype('category')</code>(其中<code>to_convert</code>是问题中定义的一组列)。</p>