擅长:python、mysql、java
<p>使用<a href="https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.replace.html" rel="nofollow noreferrer">^{<cd1>}</a>的嵌套字典语法</p>
<pre><code>df2 = df.replace({'gpa':{'junk':'NaN'}})
</code></pre>
<p>从文档中:</p>
<blockquote>
<p>Nested dictionaries, e.g., {‘a’: {‘b’: nan}}, are read as follows: look in column ‘a’ for the value ‘b’ and replace it with nan.</p>
</blockquote>
<p>请注意,使用<code>'NaN'</code>将用字符串替换它。如果希望它是实际的<code>NaN</code>,请使用<code>np.nan</code></p>