python-2.7 - 只有非零值 Python 列表

Question

我只想从 python 列表中提取非零数字。这就是我正在做的。但它似乎不起作用。

d=[num if num for num in d]

where d is my original list and again I want output in same list

Answer 1

In [5]: d =[1,2,3,0,0,9]

In [6]: d = filter(None,d) 

In [7]: d
Out[7]: [1, 2, 3, 9]

一些时间:

In [30]: %timeit filter(None,d)
1000000 loops, best of 3: 727 ns per loop

In [31]: %timeit filter(lambda x: x != 0, d)
100000 loops, best of 3: 3.89 µs per loop

In [32]: %timeit [x for x in d if x != 0]
100000 loops, best of 3: 2.33 µs per loop

In [33]: %timeit  [num for num in d if num]
100000 loops, best of 3: 2.04 µs per loop

因为列表中只有数字 filter(None,d) 可以正常工作。如果您有任何其他虚假值，如空列表 [] 等。它也会删除它们。