擅长:python、mysql、java
<p>您可以使用字典通过<code>ticker, quarter, year</code>索引<code>B</code>,这样查找就很容易了</p>
<pre><code>releasedates = [('AAPL', 1, 2010), ('AAPL', 2, 2010), ('AAPL', 3, 2010),
('AAPL', 4, 2010)]
B = [('AAPL', 1, 2010, 2), ('AAPL', 4, 2010, 10)]
# index wanted values
B_index = {item[:3]:item[3] for item in B}
output = [(ticker, quarter, year, B_index.get((ticker, quarter, year), 0))
for ticker, quarter, year in releasedates]
print(output)
</code></pre>