擅长:python、mysql、java
<p>下面呢?(假设<code>customer_email</code>在df2中是唯一的):</p>
<pre><code>df3 = pd.merge(df1, df2, on=['customer_Email'], how="left")
df3["count"] = df3.groupby("customer_Email").cumcount()
df3.loc[df3["count"]>0,"Fraud"] = "N/A"
df3[["customer_Email","Fraud","ID"]]
</code></pre>
<p>输出:</p>
<pre><code> customer_Email Fraud ID
0 name_0 False 0
1 name_1 True 1
2 name_1 N/A 5
3 name_2 True 2
4 name_3 True 3
5 name_4 False 4
6 name_1 N/A 1
7 name_1 N/A 5
</code></pre>