擅长:python、mysql、java
<p>试试这个</p>
<pre><code>(
dfB.date.map(
dfA.set_index('date')['amount'].to_dict()
).fillna(0.0)
)
</code></pre>
<p>或</p>
<pre><code>(
dfB.merge(
dfA, on=['client_id', 'date'], suffixes=("_x", ""), how='left'
).fillna(0.0).drop(columns=["amount_x"])
)
</code></pre>
<hr/>
<pre><code> client_id date amount
0 1 2020-07-11 100.0
1 1 2020-07-10 90.0
2 1 2020-07-09 80.0
3 1 2020-07-07 0.0
4 1 2020-07-06 0.0
5 1 2020-07-05 0.0
5 1 2020-07-04 0.0
3 1 2020-07-03 0.0
4 1 2020-07-02 0.0
5 1 2020-07-01 86.0
</code></pre>