擅长:python、mysql、java
<p>您可以在创建组后尝试反向求和,然后屏蔽:</p>
<pre><code>s = df['Entries'].gt(0).cumsum()
u= df['Entries'][::-1].groupby(s).cumsum().mask(df['Entries'].le(0),0)
out = df.assign(New_Entries=u) # you can assign to the original column too.
</code></pre>
<hr/>
<pre><code>print(out)
ID Date Entries New_Entries
0 1 2013 100 100
1 1 2014 0 0
2 1 2015 60 30
3 1 2016 -30 0
4 1 2017 0 0
5 1 2018 50 30
6 1 2019 0 0
7 1 2020 -20 0
8 2 2013 100 100
9 2 2014 0 0
10 2 2015 60 30
11 2 2016 -30 0
12 2 2017 0 0
13 2 2018 50 30
14 2 2019 0 0
15 2 2020 -20 0
</code></pre>