python - 如何在Python中解析和打印树

Question

目前我有以下格式的数据

A
A -> B -> C -> D -> Z
A -> B -> O
A -> X

这存储在列表中 [line1、line2 等]

现在我想按以下方式打印它

 A
 |- X
 |- B
    |- O
    |- C
       |- D
          |- Z

我是Python新手，所以。我正在考虑在数组中的每个元素中找到“->”并用空格替换。我不知道该往前走。

Answer 1

这里有一些代码可以帮助您入门(根据需要添加您自己的美化):

>>> def make_links(data):
        'Create a dictionary mapping nodes to a set of their successors'
        links = {}
        for row in data:
            nodes = row.replace(' ', '').split('->')
            for a, b in zip(nodes[:-1], nodes[1:]):
                links.setdefault(a, set()).add(b)
        return links

>>> def draw_tree(links, start, depth=0):
        'Recursively print a tree from a given starting point and given depth'
        print('   ' * depth + start)
        for node in sorted(links.get(start, [])):
            draw_tree(links, node, depth+1)

>>> data = ['A', 'A -> B -> C -> D -> Z', 'A -> B -> O', 'A -> X']

>>> links = make_links(data)
>>> links
{'A': {'X', 'B'}, 'C': {'D'}, 'B': {'C', 'O'}, 'D': {'Z'}}

>>> draw_tree(links, start='A')
A
   B
      C
         D
            Z
      O
   X