擅长:python、mysql、java
<p>你可以通过链接另一个<code>groupby</code>来获得我想要的:</p>
<pre><code>arrays = [np.array(['bar', 'bar', 'bar', 'foo', 'foo', 'foo']),
np.array(['one', 'two', 'three', 'one', 'two', 'three'])]
df = pd.DataFrame([1000, 800, 500, 800, 400, 200], index=arrays)
bar one 1000
two 800
three 500
foo one 800
two 400
three 200
expected_result = pd.DataFrame([Nan, -200, -500, Nan, -400, -600], index=arrays)
df.groupby(level=0).diff().groupby(level=0).cumsum()
bar one Nan
two -200
three -500
foo one Nan
two -400
three -600
</code></pre>