javascript 如何获取未知 JSON 层次结构的总深度？
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How to get the total depth of an unknown JSON hierarchy?
提问by jfk83
I've been struggling to find/build a recursive function to parse this JSON file and get the total depth of its children.
我一直在努力寻找/构建一个递归函数来解析这个 JSON 文件并获取其子项的总深度。
The file looks something like this:
该文件如下所示：
var input = {
"name": "positive",
"children": [{
"name": "product service",
"children": [{
"name": "price",
"children": [{
"name": "cost",
"size": 8
}]
}, {
"name": "quality",
"children": [{
"name": "messaging",
"size": 4
}]
}]
}, {
"name": "customer service",
"children": [{
"name": "Personnel",
"children": [{
"name": "CEO",
"size": 7
}]
}]
}, {
"name": "product",
"children": [{
"name": "Apple",
"children": [{
"name": "iPhone 4",
"size": 10
}]
}]
}]
}
回答by Christopher Chiche
You can use a recursive function to go through the whole tree:
您可以使用递归函数遍历整个树：
getDepth = function (obj) {
var depth = 0;
if (obj.children) {
obj.children.forEach(function (d) {
var tmpDepth = getDepth(d)
if (tmpDepth > depth) {
depth = tmpDepth
}
})
}
return 1 + depth
}
The function works as follow:
该函数的工作原理如下：
- If the object is not a leaf (i.e the object has the children attribute), then:
- Compute the depth of each child, save the maximal one
- return 1 + the depth of the deepest child
- Otherwise, return 1
- 如果对象不是叶子（即对象具有 children 属性），则：
- 计算每个孩子的深度，保存最大的一个
- return 1 + 最深孩子的深度
- 否则返回 1
jsFiddle: http://jsfiddle.net/chrisJamesC/hFTN8/
jsFiddle：http: //jsfiddle.net/chrisJamesC/hFTN8/
EDITWith modern JavaScript, the function could look like this:
编辑使用现代 JavaScript，该函数可能如下所示：
const getDepth = ({ children }) => 1 +
(children ? Math.max(...children.map(getDepth)) : 0)
jsFiddle: http://jsfiddle.net/chrisJamesC/hFTN8/59/
jsFiddle：http: //jsfiddle.net/chrisJamesC/hFTN8/59/
回答by minikomi
This will count the number of "leaves" in a tree:
这将计算树中“叶子”的数量：
var treeCount = function (branch) {
if (!branch.children) {
return 1;
}
return branch.children.reduce(function (c, b) {
return c + treeCount(b);
}, 0)
}
And an alternative way to get depth:
以及获得深度的另一种方法：
var depthCount = function (branch) {
if (!branch.children) {
return 1;
}
return 1 + d3.max(branch.children.map(depthCount));
}
