擅长:python、mysql、java
<p>您可以使用<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.melt.html" rel="nofollow">melt</a>:</p>
<pre><code>(pd.melt(df, id_vars=['quantity'], value_vars=['buyer', 'seller'],
value_name='trader', var_name='tradetype')
.groupby(['tradetype', 'trader'])
.sum()
.unstack(level=0)
.fillna(0)
.quantity
.rename(columns={'buyer': 'totalbuy', 'seller': 'totalsell'})
)
tradetype totalbuy totalsell
trader
Frank 5 0
Jesse 0 4
John 14 5
Mark 0 10
</code></pre>