Question

我有一个这样的清单：

a = [[None, None, None],
     [None, None, None],
     [40.069, 18.642, 1.0],
     [41.18, 19.467, 1.0],
     [None, None, None]]

我希望这就像这样。做这个的最好方式是什么？谢谢

b = [[40.069, 18.642, 1.0], [41.18, 19.467, 1.0]]

Answer 1

您可以使用filter：

filtered = list(filter(any, a))

Answer 2

您可以使用：

 b = [i for i in a if i.count(None) != len(i)]

Answer 3

以下内容完全符合您的要求（包括保留任何不是全部None的子列表，即使您未在示例数据中显示这样的子列表）：

a = [[None, None, None],
     [None, None, None],
     [40.069, 18.642, 1.0],
     [41.18, 19.467, 1.0],
     [None, None, None],
     [42.13, None, 1.5]]  # added mixed case

b = []
for sublist in a:
    cleaned = [elem for elem in sublist if elem is not None]
    if len(cleaned):  # anything left?
        b.append(cleaned)

print(b)

输出：

[[40.069, 18.642, 1.0],
 [41.18, 19.467, 1.0],
 [42.13, 1.5]]

Answer 4

for lst in a:
 if all(x is None for x in lst):
    pass
 else:
    b.append(lst)

Answer 5

您的子列表似乎是None值列表或浮点值列表。这意味着您可以使用简单的list comprehension来过滤列表a，方法是检查每个列表的第一项是否为None：

>>> a = [[None, None, None],
...      [None, None, None],
...      [40.069, 18.642, 1.0],
...      [41.18, 19.467, 1.0],
...      [None, None, None]]
>>> b = [x for x in a if x[0] is not None]
>>> b
[[40.069, 18.642, 1.0], [41.18, 19.467, 1.0]]
>>>

如何从列表列表中删除无元素

5 个答案: