擅长:python、mysql、java
<p>您可以使用.loc索引:</p>
<pre><code>df = pd.DataFrame({'Effective_Date':pd.date_range('2019-01-01', periods = 6),
'Cancellations':['Yes'] * 4 + ['No'] * 2,
'Lapses':['Yes'] * 2 + ['No'] * 4})
df
Effective_Date Cancellations Lapses
0 2019-01-01 Yes Yes
1 2019-01-02 Yes Yes
2 2019-01-03 Yes No
3 2019-01-04 Yes No
4 2019-01-05 No No
5 2019-01-06 No No
df["Termination_Date"] = df.loc[(df["Cancellations"] == "Yes") | (df["Lapses"] == "Yes"), "Effective_Date"]
Effective_Date Cancellations Lapses Termination_Date
0 2019-01-01 Yes Yes 2019-01-01
1 2019-01-02 Yes Yes 2019-01-02
2 2019-01-03 Yes No 2019-01-03
3 2019-01-04 Yes No 2019-01-04
4 2019-01-05 No No NaT
5 2019-01-06 No No NaT
</code></pre>