Python创建列表组合

Question

我有一个包含元素和元素序列计数的字典。我想创建一个由这些元素组合而成的列表

示例

Input: dictElement = {"PA":2,"PB":2}

Expected Output:
[('PB0', 'PA0'),
('PB0', 'PA1'),
('PB1', 'PA0'),
('PB1', 'PA1')]

---

Input: dictElement = {"PA":2,"PB":2,"PC":3}

Expected Output:
[('PC0', 'PB0', 'PA0'), 
('PC0', 'PB0', 'PA1'), 
('PC0', 'PB1', 'PA0'), 
('PC0', 'PB1', 'PA1'), 
('PC1', 'PB0', 'PA0'), 
('PC1', 'PB0', 'PA1'), 
('PC1', 'PB1', 'PA0'), 
('PC1', 'PB1', 'PA1'), 
('PC2', 'PB0', 'PA0'), 
('PC2', 'PB0', 'PA1'), 
('PC2', 'PB1', 'PA0'), 
('PC2', 'PB1', 'PA1')]

注：字典的数字元素可以更改

Answer 1

您还没有指定字典的键在输出中的处理顺序。如果采用反向排序顺序，则可以使用itertools.product()轻松地执行此操作：

from itertools import product

combinations = product(*(['{0}{1}'.format(v, i) for i in range(dictElement[v])] 
                         for v in sorted(dictElement, reverse=True))

演示：

>>> from itertools import product
>>> dictElement = {"PA":2,"PB":2,"PC":3}
>>> combinations = product(*(['{0}{1}'.format(v, i) for i in range(dictElement[v])]
...                           for v in sorted(dictElement, reverse=True)))
>>> for combo in combinations:
...     print(combo)
...
('PC0', 'PB0', 'PA0')
('PC0', 'PB0', 'PA1')
('PC0', 'PB1', 'PA0')
('PC0', 'PB1', 'PA1')
('PC1', 'PB0', 'PA0')
('PC1', 'PB0', 'PA1')
('PC1', 'PB1', 'PA0')
('PC1', 'PB1', 'PA1')
('PC2', 'PB0', 'PA0')
('PC2', 'PB0', 'PA1')
('PC2', 'PB1', 'PA0')
('PC2', 'PB1', 'PA1')