JS/JQuery：無法訪問json中的數組元素

Question

我正在處理頁面上的圖表。自從我與工作的Django，我得的數據JSON傳遞到HTML，然後解析JSON來獲取數據。

的問題是，控制檯說：

Uncaught TypeError: Cannot read property '0' of undefined(…)

function drawChart() { 
    var google_chart_json = {"MyKey": [[[2016, 11, 2], 156.0], [[2016, 11, 3], 69.0], [[2016, 11, 4], 126.0], [[2016, 11, 5], 67.0], [[2016, 11, 6], 97.0], [[2016, 11, 7], 193.0], [[2016, 11, 8], 96.0], [[2016, 11, 9], 64.0], [[2016, 11, 10], 117.0], [[2016, 11, 11], 190.0]]}; 

    $.each(google_chart_json, function (key, val) { 
     console.log(key); 
     $.each(val,function (scan) { 
      var year = scan[0][0] 
      console.log(year) 
     }) 
    }); 
    .... 

正如你可以看到var year應該是2016等

問題出在哪裏？

Answer 1

傳遞給$.each回調的第一個參數是一個鍵或數組索引。第二個參數是值。你在外面$.each有這個權利，但不是內在的。

修正：

function drawChart() { 
 
    var google_chart_json = { 
 
    "MyKey": [ 
 
     [[2016, 11, 2], 156.0], 
 
     [[2016, 11, 3], 69.0], 
 
     [[2016, 11, 4], 126.0], 
 
     [[2016, 11, 5], 67.0], 
 
     [[2016, 11, 6], 97.0], 
 
     [[2016, 11, 7], 193.0], 
 
     [[2016, 11, 8], 96.0], 
 
     [[2016, 11, 9], 64.0], 
 
     [[2016, 11, 10], 117.0], 
 
     [[2016, 11, 11], 190.0] 
 
    ] 
 
    }; 
 

 
    $.each(google_chart_json, function(key, val) { 
 
    console.log(key); 
 
    $.each(val, function(idx, scan) { 
 
     var year = scan[0][0] 
 
     console.log(year) 
 
    }) 
 
    }); 
 
} 
 

 
drawChart();

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Answer 2

的問題是，在scan你的內心僅環是關鍵值（或在這種情況下，數組的索引，0-9），而不是完整的數組。

$.each(google_chart_json, function (key, val) { 
    console.log(key); 
    $.each(val,function (scan) { 
     console.log(google_chart_json[key][scan][0][0]) 
    }) 
});