擅长:python、mysql、java
<p>您可以使用<code>defaultdict</code>:</p>
<pre><code>>>> from collections import defaultdict
>>> D_grpTagReport = { ('Tag1', '1'):345.56 ,
... ('Tag1', '2'):45.6 ,
... ('Tag2', '3'):3.1 ,
... ('Tag3', '1'):21.56 ,
... ('Tag2', '3'):1.56 ,
... }
>>> result = defaultdict(int)
>>> for t in D_grpTagReport:
... result[t[0]] += D_grpTagReport[t]
...
>>> result
defaultdict(<class 'int'>, {'Tag3': 21.56, 'Tag1': 391.16, 'Tag2': 1.56})
</code></pre>