使用d3.json从PHP输出JSON

Question

我创建了一个PHP文件来查询JSON输出。对于特定的过滤器"testPHP.php?number=123“，PHP文件的JSON输出是

[{"source":"AB","target":"AC","type":"true"},{"source":"UB","target":"EP","type":"true"},{"source":"US","target":"UR","type":"lie"},{"source":"BS","target":"QW","type":"lie"},{"source":"UW","target":"EA","type":"lie"}]

我在html文件中尝试过，以读取JSON输出到链接变量

var links; // a global
d3.json("testPHP.php?number=123", function(error, json) {
  if (error) return console.warn(error);
  links = json;
});

但是，看起来数据并不是存储在链接中。如何在var links中存储数据

基本上，我希望将此https://gist.github.com/mbostock/1153292中的var links替换为来自PHP的JSON输出中的JSON。

编辑:还是http://localhost:8080导致了问题？

Answer 1

been调用是异步的；回调之后包含的代码是在填充"links“变量之前执行的。

var links; // a global
d3.json("testPHP.php?number=123", function(error, json) {
  if (error) return console.warn(error);
  links = json;

  console.log(links); // your links are populated here

  // include the rest of your app here
});

// links is still undefined here because the success callback hasn't been run yet

Answer 2

您需要编写links = [{"source":"AB","target":"AC","type":"true"},{"source":"UB","target":"EP","type":"true"},{"source":"US","target":"UR","type":"lie"},{"source":"BS","target":"QW","type":"lie"},{"source":"UW,"target":"EA","type":"lie"}]

在这一点上，链接将保存该信息。但是，您可能希望考虑一个数组。