擅长:python、mysql、java
<p>使用<code>pandas.Series.cumsum</code>:</p>
<pre><code>df['t_A'] = 17500 - df['C_B'].cumsum()
print(df)
</code></pre>
<p>输出:</p>
<pre><code> I_Code Date_1 Date_2 C_B t_A
0 4 01/09/2019 02/08/2019 7 17493
1 4 01/09/2019 03/08/2019 1189 16304
2 1 01/09/2019 04/08/2019 8 16296
3 4 01/09/2019 04/08/2019 1650 14646
4 1 01/09/2019 05/08/2019 9 14637
5 4 01/09/2019 05/08/2019 1805 12832
6 1 01/09/2019 06/08/2019 63 12769
7 2 01/09/2019 06/08/2019 2 12767
8 4 01/09/2019 07/08/2019 1985 10782
9 1 01/09/2019 08/08/2019 869 9913
10 2 01/09/2019 08/08/2019 6 9907
11 4 01/09/2019 08/08/2019 2072 7835
12 1 01/09/2019 09/08/2019 790 7045
13 4 01/09/2019 09/08/2019 2120 4925
14 1 01/09/2019 10/08/2019 1275 3650
15 1 01/09/2019 11/08/2019 1355 2295
16 4 01/09/2019 11/08/2019 2249 46
</code></pre>