检查 Python 列表中的任何项目是否为 None（但包括零）
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Check if any item in Python list is None (but include zero)
提问by Bryan
I'm trying to do a simple test that returns Trueif any of the results of a list are None. However, I want 0and ''to not cause a return of True.
我正在尝试做一个简单的测试，True如果列表的任何结果是None. 但是，我希望0并且''不会导致True.
list_1 = [0, 1, None, 4]
list_2 = [0, 1, 3, 4]
any(list_1) is None
>>>False
any(list_2) is None
>>>False
As you can see, the any()function as it is isn't being helpful in this context.
如您所见，该any()函数在此上下文中没有帮助。
采纳答案by Martijn Pieters
For listobjects can simply use a membership test:
对于list对象可以简单地使用成员资格测试：
None in list_1
Like any(), the membership test on a listwill scan all elements but short-circuit by returning as soon as a match is found.
像 一样any()， a 上的成员资格测试list将扫描所有元素，但一旦找到匹配项就会返回短路。
any()returns Trueor False, never None, so your any(list_1) is Nonetest is certainly not going anywhere. You'd have to pass in a generator expression for any()to iterate over, instead:
any()返回Trueor False， never None，所以你的any(list_1) is None测试肯定不会去任何地方。你必须传入一个生成器表达式any()来迭代，而不是：
any(elem is None for elem in list_1)
回答by Tom Cornebize
list_1 = [0, 1, None, 4]
list_2 = [0, 1, 3, 4]
any(x is None for x in list_1)
>>>True
any(x is None for x in list_2)
>>>False
