>我有以下简单的图表来可视化：
示例图形
首先，仅显示连接到其邻居"n2"的"n1">
其次，单击"n2">后，网络通过添加两条边"n2"->"n3"和"n2"->"n4"进行扩展
第三，单击"n3">后，网络通过添加两条边"n3"->"n1"和"n3"->"n5"进行扩展。
为此，我想我可以创建一个可见的节点数组。通过单击节点，此节点名称将被添加到数组中。然后在 tick() 函数中，该数组中的可见节点将用于设置网络。
但是当我使用以下代码执行此操作时：
// return currently visible nodes as the source nodes
// e.g. called by
// var visible_seeds = seeding(nodes);
//
function seeding(nodes){
var visible = [];
nodes.forEach(function(n){
if(n.name=='n1')
visible.push(n);
});
return visible;
}
然后按如下方式调用上述函数：
var visible_seeds = seeding(nodes);
var force = d3.layout.force()
.nodes(d3.values(visible_seeds))
.links(links)
.size([width, height])
.linkDistance(60)
.charge(-300)
.on("tick", tick)
.start();
它给出了错误
index.html TypeError：'undefined' 不是一个函数 (评估 'nodes.forEach(function(n){...')
实现目标的正确方法是什么？谢谢你!!
附言我对D3和javascript绝对是新手。
D3 读入的数据来自 csv 文件：
source,target,value
n1,n2,1.0
n2,n3,1.0
n2,n4,1.0
n3,n1,1.0
n3,n5,1.0
我的代码基于以下示例： http://bl.ocks.org/d3noob/5155181
已添加 - 源代码 -问题发生在函数 seeding()
中<!DOCTYPE html>
<meta charset="utf-8">
<script src="http://d3js.org/d3.v3.js"></script>
<style>
path.link {
fill: none;
stroke: #666;
stroke-width: 1.5px;
}
path.link.twofive {
opacity: 0.25;
}
path.link.fivezero {
opacity: 0.50;
}
path.link.sevenfive {
opacity: 0.75;
}
path.link.onezerozero {
opacity: 1.0;
}
circle {
fill: #ccc;
stroke: #fff;
stroke-width: 1.5px;
}
text {
fill: #000;
font: 10px sans-serif;
pointer-events: none;
}
</style>
<body>
<script>
// get the data
d3.csv("force.csv", function(error, links) {
var nodes = {};
// Compute the distinct nodes from the links.
links.forEach(function(link) {
link.source = nodes[link.source] || (nodes[link.source] = {name: link.source, vis:0});
link.target = nodes[link.target] || (nodes[link.target] = {name: link.target, vis:0});
link.value = +link.value;
});
//nodes["n1"] = {name:"n1", vis:1};
var vis = ['n1'];
var width = 960,
height = 500;
function seeding(){
var visible = [];
nodes.forEach(function(n){
if(n.name=='n1')
visible.push(n);
});
return visible;
}
var visible_seeds = seeding();
var force = d3.layout.force()
.nodes(d3.values(visible_seeds))
//.nodes(d3.values(nodes))
.links(links)
.size([width, height])
.linkDistance(60)
.charge(-300)
.on("tick", tick)
.start();
// Set the range
var v = d3.scale.linear().range([0, 100]);
// Scale the range of the data
v.domain([0, d3.max(links, function(d) { return d.value; })]);
// asign a type per value to encode opacity
links.forEach(function(link) {
if (v(link.value) <= 25) {
link.type = "twofive";
} else if (v(link.value) <= 50 && v(link.value) > 25) {
link.type = "fivezero";
} else if (v(link.value) <= 75 && v(link.value) > 50) {
link.type = "sevenfive";
} else if (v(link.value) <= 100 && v(link.value) > 75) {
link.type = "onezerozero";
}
});
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
// build the arrow.
svg.append("svg:defs").selectAll("marker")
.data(["end"]) // Different link/path types can be defined here
.enter().append("svg:marker") // This section adds in the arrows
.attr("id", String)
.attr("viewBox", "0 -5 10 10")
.attr("refX", 15)
.attr("refY", -1.5)
.attr("markerWidth", 6)
.attr("markerHeight", 6)
.attr("orient", "auto")
.append("svg:path")
.attr("d", "M0,-5L10,0L0,5");
// add the links and the arrows
var path = svg.append("svg:g").selectAll("path")
.data(force.links())
.enter().append("svg:path")
.attr("class", function(d) { return "link " + d.type; })
.attr("marker-end", "url(#end)");
// define the nodes
var node = svg.selectAll(".node")
.data(force.nodes())
.enter().append("g")
.attr("class", "node")
.on("click", click)
.on("dblclick", dblclick)
.call(force.drag);
// add the nodes
node.append("circle")
.attr("r", 5);
// add the text
node.append("text")
.attr("x", 12)
.attr("dy", ".35em")
.text(function(d) { return d.name; });
// add the curvy lines
function tick() {
path.attr("d", function(d) {
var dx = d.target.x - d.source.x,
dy = d.target.y - d.source.y,
dr = Math.sqrt(dx * dx + dy * dy);
return "M" +
d.source.x + "," +
d.source.y + "A" +
dr + "," + dr + " 0 0,1 " +
d.target.x + "," +
d.target.y;
});
node
.attr("transform", function(d) {
return "translate(" + d.x + "," + d.y + ")"; });
}
// action to take on mouse click
function click() {
d3.select(this).select("text").transition()
.duration(750)
.attr("x", 22)
.style("fill", "steelblue")
.style("stroke", "lightsteelblue")
.style("stroke-width", ".5px")
.style("font", "20px sans-serif");
d3.select(this).select("circle").transition()
.duration(750)
.attr("r", 16)
.style("fill", "lightsteelblue");
}
// action to take on mouse double click
function dblclick() {
d3.select(this).select("circle").transition()
.duration(750)
.attr("r", 6)
.style("fill", "#ccc");
d3.select(this).select("text").transition()
.duration(750)
.attr("x", 12)
.style("stroke", "none")
.style("fill", "black")
.style("stroke", "none")
.style("font", "10px sans-serif");
}
});
</script>
</body>
</html>
首先，错误的根源是因为nodes是一个JavaScript对象(而不是数组)，它没有forEach方法。
其次，我不确定你的方法将走向何方。 你从一个节点开始力布局，然后呢？ 单击时，是否附加其他节点？ 您将如何处理链接？
Intead，我建议在单击时切换节点和链接的可见性。 下面是一个快速实现：
<!DOCTYPE html>
<meta charset="utf-8">
<script src="http://d3js.org/d3.v3.js"></script>
<style>
path.link {
fill: none;
stroke: #666;
stroke-width: 1.5px;
}
path.link.twofive {
opacity: 0.25;
}
path.link.fivezero {
opacity: 0.50;
}
path.link.sevenfive {
opacity: 0.75;
}
path.link.onezerozero {
opacity: 1.0;
}
circle {
fill: #ccc;
stroke: #fff;
stroke-width: 1.5px;
}
text {
fill: #000;
font: 10px sans-serif;
pointer-events: none;
}
</style>
<body>
<script>
// get the data
//d3.csv("force.csv", function(error, links) {
var links = [{"source":"n1","target":"n2","value":"1.0"},{"source":"n2","target":"n3","value":"1.0"},{"source":"n2","target":"n4","value":"1.0"},{"source":"n3","target":"n1","value":"1.0"},{"source":"n3","target":"n5","value":"1.0 "}];
var nodes = {};
// Compute the distinct nodes from the links.
links.forEach(function(link) {
link.source = nodes[link.source] || (nodes[link.source] = {name: link.source, vis:0});
link.target = nodes[link.target] || (nodes[link.target] = {name: link.target, vis:0});
link.value = +link.value;
});
//nodes["n1"] = {name:"n1", vis:1};
var vis = ['n1'];
var width = 300,
height = 300;
for (key in nodes){
var node = nodes[key];
node.visible = (node.name === 'n1');
}
var force = d3.layout.force()
.nodes(d3.values(nodes))
.links(links)
.size([width, height])
.linkDistance(60)
.charge(-300)
.on("tick", tick)
.start();
// Set the range
var v = d3.scale.linear().range([0, 100]);
// Scale the range of the data
v.domain([0, d3.max(links, function(d) { return d.value; })]);
// asign a type per value to encode opacity
links.forEach(function(link) {
if (v(link.value) <= 25) {
link.type = "twofive";
} else if (v(link.value) <= 50 && v(link.value) > 25) {
link.type = "fivezero";
} else if (v(link.value) <= 75 && v(link.value) > 50) {
link.type = "sevenfive";
} else if (v(link.value) <= 100 && v(link.value) > 75) {
link.type = "onezerozero";
}
});
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
// build the arrow.
svg.append("svg:defs").selectAll("marker")
.data(["end"]) // Different link/path types can be defined here
.enter().append("svg:marker") // This section adds in the arrows
.attr("id", String)
.attr("viewBox", "0 -5 10 10")
.attr("refX", 15)
.attr("refY", -1.5)
.attr("markerWidth", 6)
.attr("markerHeight", 6)
.attr("orient", "auto")
.append("svg:path")
.attr("d", "M0,-5L10,0L0,5");
// add the links and the arrows
var path = svg.append("svg:g").selectAll("path")
.data(force.links())
.enter().append("svg:path")
.attr("class", function(d) { return "link " + d.type; })
.attr("marker-end", "url(#end)")
.style("opacity", function(d){
return d.target.visible && d.source.visible ? 1 : 0;
})
// define the nodes
var node = svg.selectAll(".node")
.data(force.nodes())
.enter().append("g")
.attr("class", "node")
.style("opacity", function(d){
return d.visible ? 1 : 0;
})
.on("click", click)
.call(force.drag);
// add the nodes
node.append("circle")
.attr("r", 5);
// add the text
node.append("text")
.attr("x", 12)
.attr("dy", ".35em")
.text(function(d) { return d.name; });
// add the curvy lines
function tick() {
path.attr("d", function(d) {
var dx = d.target.x - d.source.x,
dy = d.target.y - d.source.y,
dr = Math.sqrt(dx * dx + dy * dy);
return "M" +
d.source.x + "," +
d.source.y + "A" +
dr + "," + dr + " 0 0,1 " +
d.target.x + "," +
d.target.y;
});
node
.attr("transform", function(d) {
return "translate(" + d.x + "," + d.y + ")"; });
}
// action to take on mouse click
function click(d0) {
links.forEach(function(d1){
console.log(d0, d1.source)
if (d1.source === d0) {
d1.target.visible = !d1.target.visible;
}
});
node.style("opacity", function(d){
return d.visible ? 1 : 0;
});
path.style("opacity", function(d){
return d.target.visible && d.source.visible ? 1 : 0;
});
}
//});
</script>
</body>
</html>