使用dict（python）中的特定键构建列表？ [英] Build a list using specific keys in a dict (python)?

问题描述

我在Python中实现Dijkstra搜索算法。在搜索结束时，我使用前导映射重建最短路径，从目标节点的前身开始。例如：

  path = [] 
 path.append（destination）
 previous = predecessor_map [destination ] 
 while previous！= origin：
 path.append（previous）
 previous = predecessor_map [previous] 
  

有没有办法用较少的代码行（例如列表理解）？

解决方案

我唯一的建议是摆脱轻微的代码重复：

  path = [] 
以前=目的地
，而之前！=起始：
 path.append（上一个）
上一页=前一个_map [上一页] 
  

除此之外，我认为你的代码实际上很清楚，不可能从任何缩短尝试中获益。

最后，值得注意的是，当 destination == origin 时，以上也可以使用，而您的原始版本最可能不会（取决于如何确定 predece ssor_map 被填充）。不知道这是否与您的用例相关。

I'm implementing the Dijkstra search algorithm in Python. At the end of the search, I reconstruct the shortest path using a predecessor map, starting with the destination node's predecessor. For example:

path = []
path.append(destination)
previous = predecessor_map[destination]
while previous != origin:
    path.append(previous)
    previous = predecessor_map[previous]

Is there any way to do this with less lines of code (e.g. list comprehension)?

解决方案

The only suggestion that I have is to get rid of the slight code duplication:

path = []
previous = destination
while previous != origin:
    path.append(previous)
    previous = predecessor_map[previous]

Beyond that, I think your code is actually very clear and is unlikely to benefit from any attempts to shorten it.

Lastly, it is worth noting that the above also works when destination == origin, whereas your original version most probably doesn't (depends on how exactly predecessor_map is populated). Don't know if this is relevant to your use cases.

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