擅长:python、mysql、java
<p>您可以使用<a href="https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.get_dummies.html" rel="nofollow noreferrer">^{<cd1>}</a>和<a href="https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.groupby.html" rel="nofollow noreferrer">^{<cd2>}</a>:</p>
<pre><code>print( pd.concat([df, pd.get_dummies(df['val'])], axis=1).groupby('id').sum().reset_index() )
</code></pre>
<p>印刷品:</p>
<pre><code> id A12 B23 C34 E45 F56 G67
0 1 1 1 1 0 0 0
1 2 1 0 1 1 1 0
2 3 0 1 0 0 0 1
</code></pre>