getJSON() 获取未定义的值

Question

我试图从 JSON 文件中解析值 "title,author and ISBN" 并将它们存储在一个名为 availableTags 的数组中，但我只得到值 undefined 和我不知道问题出在哪里。有什么建议吗？

我的代码：

$(document).ready(function () {
    var availableTags = [];

  $.getJSON( "search.json", function( data ) {

    availableTags[0] = data.title;
    availableTags[1] = data.author;
    availableTags[2] = data.ISBN;
    alert(availableTags[0]);

});
});

这是JSON代码

[{"title":"the book","author":"Peter","ISBN":"632764"}]

Answer 1

您需要注意，您的数据变量实际上是一个数组。

您需要将代码更改为：

$(document).ready(function () {
    var availableTags = [];

  $.getJSON( "search.json", function( data ) {
    data = data[0];
    availableTags[0] = data.title;
    availableTags[1] = data.author;
    availableTags[2] = data.ISBN;
    alert(availableTags[0]);

});
});

您可能漏掉了括号。

这是一个包含一项的数组。

[{"title":"the book","author":"Peter","ISBN":"632764"}]

这是一件商品。

{"title":"the book","author":"Peter","ISBN":"632764"}

Answer 2

$(document).ready(function () {
    var availableTags = [];

  $.getJSON( "search.json", function( data ) {
    //use data[0] instead of data 
    var book = data[0];
    availableTags[0] = book.title;
    availableTags[1] = book.author;
    availableTags[2] = book.ISBN;
    alert(availableTags[0]);

});
});

Answer 3

好吧，有点晚了，但既然我写了一些东西，也许它对某人有帮助：

$(document).ready(function() {

  var searchResults = [];

  // Assuming data will be something like this
  // data = [{"title":"the book","author":"Peter","ISBN":"632764"},{"title":"the other book","author":"Sebastian","ISBN":"123456"}];

  $.getJSON("search.json", function(data) {

    if (typeof data === 'object' && data.length > 0) {

      searchResults = data;
      console.info('Referenced to outside variable');

      for (var amount = 0; amount < searchResults.length; amount++) {
        var result = searchResults[amount];

        // do something with each result here

        console.group('Search-Result:');
        console.log('Title: ', result.title);
        console.log('Author: ', result.author);
        console.log('ISBN: ', result.ISBN);
        console.groupEnd();

      }
    } else {
      console.error('Received wrong data, expecting data to be array');
    }

  });
});

getJSON() 获取未定义的值

getJSON() getting undefined values

jquery

json

getjson