递归地在python中构建分层的JSON树 [英] recursively build hierarchical JSON tree in python
问题描述
我有一个父子连接的数据库。数据看起来像下面的,但可以以任何你想要的方式(字典,列表列表,JSON等)。
links =((Tom,Dick),(Dick,Harry), ,Larry),(Bob,Leroy),(Bob,Earl))
b $ b
我需要的输出是一个分层的JSON树,将使用d3呈现。在数据中有离散子树,我将附加到根节点。所以我需要递归地去经历链接,并建立树结构。我可以得到的最远的是遍历所有的人,并追加他们的孩子,但我不能想出做更高阶的链接(例如如何附加一个有孩子的人到别人的孩子)。这类似于。
I have a database of parent-child connections. The data look like the following but could be presented in whichever way you want (dictionaries, list of lists, JSON, etc).
links=(("Tom","Dick"),("Dick","Harry"),("Tom","Larry"),("Bob","Leroy"),("Bob","Earl"))
The output that I need is a hierarchical JSON tree, which will be rendered with d3. There are discrete sub-trees in the data, which I will attach to a root node. So I need to recursively go though the links, and build up the tree structure. The furthest I can get is to iterate through all the people and append their children, but I can't figure out to do the higher order links (e.g. how to append a person with children to the child of someone else). This is similar to another question here, but I have no way to know the root nodes in advance, so I can't implement the accepted solution.
I am going for the following tree structure from my example data.
{
"name":"Root",
"children":[
{
"name":"Tom",
"children":[
{
"name":"Dick",
"children":[
{"name":"Harry"}
]
},
{
"name":"Larry"}
]
},
{
"name":"Bob",
"children":[
{
"name":"Leroy"
},
{
"name":"Earl"
}
]
}
]
}
This structure renders like this in my d3 layout.
To identify the root notes you can unzip links
and look for parents who are not children:
parents, children = zip(*links)
root_nodes = {x for x in parents if x not in children}
Then you can apply the recursive method:
import json
links = [("Tom","Dick"),("Dick","Harry"),("Tom","Larry"),("Bob","Leroy"),("Bob","Earl")]
parents, children = zip(*links)
root_nodes = {x for x in parents if x not in children}
for node in root_nodes:
links.append(('Root', node))
def get_nodes(node):
d = {}
d['name'] = node
children = get_children(node)
if children:
d['children'] = [get_nodes(child) for child in children]
return d
def get_children(node):
return [x[1] for x in links if x[0] == node]
tree = get_nodes('Root')
print json.dumps(tree, indent=4)
I used a set to get the root nodes, but if order is important you can use a list and remove the duplicates.
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