擅长:python、mysql、java
<p>可以使用<a href="https://docs.python.org/3/library/functions.html#any" rel="nofollow">^{<cd1>}</a>和<a href="http://legacy.python.org/dev/peps/pep-0289/" rel="nofollow">generator expression</a>:</p>
<pre><code>if any(x['a'] for x in list):
# Do stuff
</code></pre>
<p>请参见下面的演示:</p>
<pre><code>>>> lst = []
>>> for i in xrange(4):
... lst.append({})
... lst[i]['a'] = False
...
>>> any(x['a'] for x in lst)
False
>>> lst[2]['a'] = True # Set an 'a' value to True
>>> any(x['a'] for x in lst)
True
>>>
</code></pre>
<p>另外,应该避免将变量命名为<code>list</code>。这样做会使内置的功能黯然失色</p>