How to check if all items in the list are None?

Question

In [27]: map( lambda f,p: f.match(p), list(patterns.itervalues()), vatids ) Out[27]: [None, <_sre.SRE_Match object at 0xb73bfdb0>, None] 

The list can be all None or one of it is an re.Match instance. What one liner check can I do on the returned list to tell me that the contents are all None?

Answer 1

all(v is None for v in l) 

will return True if all of the elements of l are None

Note that l.count(None) == len(l) is a lot faster but requires that l be an actual list and not just an iterable.

Answer 2

not any(my_list) 

returns True if all items of my_list are falsy.

Edit: Since match objects are always truthy and None is falsy, this will give the same result as all(x is None for x in my_list) for the case at hand. As demonstrated in gnibbler's answer, using any() is by far the faster alternative.