python - 在 python 中进行组合

Question

我有四个值(value)观

age = 23
gender = "M"
city ="Delhi"
religion = "Muslim"

我需要将这些按空值组合排列，例如 -

23 * * *
23 M * *
23 M Delhi *
23 M Delhi Muslim
* M * *
* M Delhi *
* M Delhi Muslim
* * Delhi *
* * Delhi Muslim
* * * Muslim
* * * *

我需要按列表中的维数升序排列。因此具有一个值的组合应该在最前面。我有大约 30 多个属性，所以我需要一种在 Python 中自动执行此操作的方法

有什么想法吗？

Answer 1

以下情况如何:

In [21]: attrib = (23, "M", "Delhi", "Muslim")

In [25]: comb = list(itertools.product(*((a, None) for a in attrib)))

In [26]: comb
Out[26]: 
[(23, 'M', 'Delhi', 'Muslim'),
 (23, 'M', 'Delhi', None),
 (23, 'M', None, 'Muslim'),
 (23, 'M', None, None),
 (23, None, 'Delhi', 'Muslim'),
 (23, None, 'Delhi', None),
 (23, None, None, 'Muslim'),
 (23, None, None, None),
 (None, 'M', 'Delhi', 'Muslim'),
 (None, 'M', 'Delhi', None),
 (None, 'M', None, 'Muslim'),
 (None, 'M', None, None),
 (None, None, 'Delhi', 'Muslim'),
 (None, None, 'Delhi', None),
 (None, None, None, 'Muslim'),
 (None, None, None, None)]

现在，如果我正确理解了您的排序要求，则应该执行以下操作:

In [27]: sorted(comb, key=lambda x:sum(v is not None for v in x))
Out[27]: 
[(None, None, None, None),
 (23, None, None, None),
 (None, 'M', None, None),
 (None, None, 'Delhi', None),
 (None, None, None, 'Muslim'),
 (23, 'M', None, None),
 (23, None, 'Delhi', None),
 (23, None, None, 'Muslim'),
 (None, 'M', 'Delhi', None),
 (None, 'M', None, 'Muslim'),
 (None, None, 'Delhi', 'Muslim'),
 (23, 'M', 'Delhi', None),
 (23, 'M', None, 'Muslim'),
 (23, None, 'Delhi', 'Muslim'),
 (None, 'M', 'Delhi', 'Muslim'),
 (23, 'M', 'Delhi', 'Muslim')]

我在您使用 * 的地方使用了 None，但使用后者很简单。

当然，对于 30 个属性，您正在查看大约 10 亿个组合，因此通过后续排序来展平列表可能行不通。但是，无论如何，您可以用 10 亿个条目做什么？