D3：另一个“无法读取未定义的属性”权重”。 [英] D3: Yet another "Cannot read property 'weight' of undefined"

问题描述

我正在尝试创建一个带有力的图形，它有一个转折：节点和链接数据来自外部定义的类。当我运行它时，我得到了可怕的和熟悉的消息：

I'm trying to create a force-directed graph with one twist: the node and link data comes from externally defined classes. When I run it, I get the dreaded and familiar message:

Uncaught TypeError: Cannot read property 'weight' of undefined

我已阅读 d3：无法读取d3.force实现中未定义的属性'weight'和出色的 https://stackoverflow.com / a / 15060978/558639 。但是没有喜悦。

I've read d3: Cannot read property 'weight' of undefined in d3.force implementation and the excellent https://stackoverflow.com/a/15060978/558639. But no joy.

我在 https：/中创建了一个JSFiddle /jsfiddle.net/3xcaqaLc/8/ 忠实地复制错误。

文档在链接上提到了权重属性，但是并不清楚我是否需​​要提供该属性。

The docs mentions a 'weights' property on the links, but it wasn't particularly clear if I needed to provide that.

我添加了 weight：每个链接的1.0 属性。

我向每个节点添加了 weight：1.0 属性。

I added a weight: 1.0 property to each node. No joy.

我发现的所有示例都显示了零链接基于索引的节点数组。取而代之的是，我使用指向节点本身的引用来构建链接。但是根据＃force.nodes（）的文档，这应该可以工作（注意使用单词 may）：

All the examples I found show the links constructed with zero-based indexes into the nodes array. Instead, I'm constructing the links with references to the nodes themselves. But according to the documentation for #force.nodes(), this should work (note the use of the word 'may'):

注意：源和目标属性的值最初可能是
，它被指定为节点数组的索引；

Note: the values of the source and target attributes may be initially specified as indexes into the nodes array; these will be replaced by references after the call to start.

也许这些文档是不准确的，但是我们欢迎您提出解决方案！

Perhaps the documents are inaccurate, but solutions will be welcome!

推荐答案

真正的原因是链接 g_graph.links 是格式与 https://github.com/mbostock/d3 / wiki / Force-Layout＃links

The real reason is that the link g_graph.links is not in the correct format as mentioned in https://github.com/mbostock/d3/wiki/Force-Layout#links

以下是节点
https://github.com/mbostock/d3/wiki/Force-Layout#nodes

这就是强制布局不起作用的原因。

That is the reason why force layout is not working.

我已注释节点，并绘制了链接部分和图形，因为刻度函数正在放置节点

I have commented the nodes and link section and graph is drawn because tick function is placing the node and the link.

  var force = d3.layout.force()
    .charge(-120)
    .linkDistance(30)
    .size([view_width, view_height])
    //.nodes(g_graph.nodes)
    //.links(g_graph.links)
    .start();

工作示例这里

希望这会有所帮助！

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