擅长:python、mysql、java
<p>尝试以下操作:</p>
<pre><code>import numpy as np
df.groupby(['Items']).apply(lambda x:
np.select([x['Type'] == 'SELL', x['Type'] == 'BUY'], [x['Qty']*-1, x['Qty']])
).apply(sum).rename('Qty').to_frame().assign(
Type = lambda x: np.select([x['Qty'] <0, x['Qty']>0, x['Qty']==0], ['SELL', 'BUY', None]),
Qty = lambda x: x['Qty'].abs()
).dropna()
</code></pre>
<p>输出:</p>
^{pr2}$