访问特定 JSON 数据答案

【问题标题】：Accessing Specific JSON Data访问特定 JSON 数据
【发布时间】：2015-06-24 16:46:48
【问题描述】：

我有一个 JSON 数据馈送，我正在尝试访问特定值，但似乎无法使其正常工作。

这是返回的 JSON 数据。

{"pollenForecast":{"zip":"37201","city":"NASHVILLE","state":"TN","forecast":[3.9,3.9,3.6,0.5],"pp":"Grass and Poplar/Cottonwood.","timestamp":"Jun 24, 2015 11:50:34 AM"},
"weatherForecast":{"date":"Jun 24, 2015 12:38:00 PM","city":"Nashville","state":"TN","zip":"37201","forecast":[
{"lowF":71,"highF":93,"iconDay":"3000","iconNight":"3100","skyDay":30,"skyNight":31,"phraseDay":"Partly Cloudy","phraseNight":"Clear","date":"Jun 24, 2015 12:00:00 AM"},    
{"lowF":74,"highF":97,"iconDay":"3200","iconNight":"7200","skyDay":32,"skyNight":4,"phraseDay":"Sunny","phraseNight":"Thunderstorms Late","date":"Jun 25, 2015 12:00:00 AM"},
{"lowF":71,"highF":87,"iconDay":"400","iconNight":"400","skyDay":4,"skyNight":4,"phraseDay":"Thunderstorms","phraseNight":"Thunderstorms","date":"Jun 26, 2015 12:00:00 AM"},
{"lowF":62,"highF":78,"iconDay":"6203","iconNight":"2900","skyDay":38,"skyNight":29,"phraseDay":"AM Thunderstorms","phraseNight":"Partly Cloudy","date":"Jun 27, 2015 12:00:00 AM"},
{"lowF":61,"highF":84,"iconDay":"3400","iconNight":"3100","skyDay":34,"skyNight":31,"phraseDay":"Mostly Sunny","phraseNight":"Clear","date":"Jun 28, 2015 12:00:00 AM"},
{"lowF":66,"highF":87,"iconDay":"3400","iconNight":"3300","skyDay":34,"skyNight":33,"phraseDay":"Mostly Sunny","phraseNight":"Mostly Clear","date":"Jun 29, 2015 12:00:00 AM"}]},"result":true}

我正在尝试访问括号内的“pollenForecast”-“预测”数字，但似乎无法正常工作。

谢谢..

function pollen_quality() {
    $.ajax({ 
        type: 'GET', 
        url: '<?php echo $pollen_quality_url; ?>', 
        dataType: 'json',
        success: function(pollen) {
            pollen = pollen.replace(/[\[\]']+/g,'');
            var pollenForecast = pollen.split(':');;
            pollenForecast = pollenForecast[5].split(',');
            //build pollen quality from pollen forecast value
            if (pollenForecast[0] == null) {
                html = '<h1><?php echo $kiosk_pollen_quality_title ?></h1><p class="no_air_quality_data">No Data</p>';
            }
            else {
                if ((pollenForecast[0] >= 0) && (pollenForecast[0] <= 2.4)) {
                    html = '<h1><?php echo $kiosk_pollen_quality_title ?></h1><p style="color: #00FF00;">Low</p>';
                }
                else if ((pollenForecast[0] >= 2.5) && (pollenForecast[0] <= 4.8)) {
                    html = '<h1><?php echo $kiosk_pollen_quality_title ?></h1><p style="color: #99FF00;">Low-Medium</p>';
                }
                else if ((pollenForecast[0] >= 4.9) && (pollenForecast[0] <= 7.2)) {
                    html = '<h1><?php echo $kiosk_pollen_quality_title ?></h1><p style="color: #FFFF00;">Medium</p>';
                }
                else if ((pollenForecast[0] >= 7.3) && (pollenForecast[0] <= 9.6)) {
                    html = '<h1><?php echo $kiosk_pollen_quality_title ?></h1><p style="color: #FF9900;">Medium-High</p>';
                }
                else { //pollen level 9.7 - 12.0
                    html = '<h1><?php echo $kiosk_pollen_quality_title ?></h1><p style="color: #FFFFFF;">High</p>';
                }
            }
            $('#pollen_quality').html(html);
        }
    });
}

【问题讨论】：

给我看一些代码。你试过什么？哪里失败了？
pollenForecast.forecast[0] 会给出 3.9，我想，我可以知道你的代码吗，参考这个jsfiddle.net/ZigmaEmpire/uyjLwh2b

标签： jquery ajax json getjson

【解决方案1】：

例如，当使用jQuery.post() 时（没关系，假设返回的 JSON 在data 中），您可以获得pollenForeCast，如下所示：

$.post( "ajax/test.html", function( data ) {
  var pollenForeCasts = data.pollenForeCast.forecast;
  for (var i = 0; i < pollenForeCasts.length; i++) {
    alert(pollenForeCasts[i]);
});

如果我没记错的话。

【讨论】：

【解决方案2】：

您可以通过以下方式访问它：

pollenForecast.forecast

= [3.9, 3.9, 3.6, 0.5]

要访问这个结果数组：

pollenForecast.forecast[0]

= 3.9

如果你想遍历它，那么只需使用：

var forecast = pollenForecast.forecast,
    forecastlen = forecast.length;

for(var i = 0; i <= forecastlen; i++){
  console.log(forecast[i]);
}

【讨论】：