Question

我正在尝试使用.pop（）函数来获取我的数组的最后一个元素（这是我在网页上显示的计数）。我对Javascript / Jquery很新，所以我对此有点挣扎......

var notif_count = data.pop();

我收到错误“Uncaught TypeError：data.pop不是函数”

我在控制台中的数据看起来像一个多维数组，但我不确定？以下是输出示例：

EDIT 2 - 输出是一个包含此处显示的字符的字符串。

[
  [
    {
      "_can_chaccess": true,
      "_can_chown": true,
      "_can_delete": true,
      "_can_modify": true,
      "_can_read": true,
      "created_at": "Wed Jan 04 17:33:13 UTC 2017",
      "created_by": 25206,
      "created_by_user[login_name]": "jamie.lowe@workbooks.com",
      "created_by_user[person_name]": "Jamie Lowe",
      "created_through": "Workbooks",
      "created_through_reference": "",
      "id": 117662,
      "imported": false,
      "key": "notifications",
      "key10": "",
      "key11": "",
      "key12": "",
      "key13": "",
      "key14": "",
      "key15": "",
      "key16": "",
      "key17": "",
      "key18": "",
      "key19": "",
      "key2": "292801",
      "key3": "47930",
      "key4": "CASE-32109",
      "key5": "",
      "key6": "",
      "key7": "",
      "key8": "",
      "key9": "",
      "lock_version": 0,
      "owner[login_name]": "jamie.lowe@workbooks.com",
      "owner[person_name]": "Jamie Lowe",
      "owner_id": 25206,
      "type": "Private::Automation::ApiData",
      "updated_at": "Wed Jan 04 17:33:13 UTC 2017",
      "updated_by": 25206,
      "updated_by_user[login_name]": "xxxx@workbooks.com",
      "updated_by_user[person_name]": "Jamie Lowe",
      "value": ""
    },
    {
      "_can_chaccess": true,
      "_can_chown": true,
      "_can_delete": true,
      "_can_modify": true,
      "_can_read": true,
      "created_at": "Wed Jan 04 17:23:21 UTC 2017",
      "created_by": 25206,
      "created_by_user[login_name]": "jamie.lowe@workbooks.com",
      "created_by_user[person_name]": "Jamie Lowe",
      "created_through": "Workbooks",
      "created_through_reference": "",
      "id": 117660,
      "imported": false,
      "key": "notifications",
      "key10": "",
      "key11": "",
      "key12": "",
      "key13": "",
      "key14": "",
      "key15": "",
      "key16": "",
      "key17": "",
      "key18": "",
      "key19": "",
      "key2": "292801",
      "key3": "47930",
      "key4": "CASE-32106",
      "key5": "",
      "key6": "",
      "key7": "",
      "key8": "",
      "key9": "",
      "lock_version": 2,
      "owner[login_name]": "jamie.lowe@workbooks.com",
      "owner[person_name]": "Jamie Lowe",
      "owner_id": 25206,
      "type": "Private::Automation::ApiData",
      "updated_at": "Wed Jan 04 17:30:39 UTC 2017",
      "updated_by": 25206,
      "updated_by_user[login_name]": "xxxx@workbooks.com",
      "updated_by_user[person_name]": "Jamie Lowe",
      "value": ""
    }
  ],
  2
]

基本上我正试图在结束前的数组末尾获得数字2 - 我该怎么做？

编辑：完整代码示例

var notif_count = data[1]; <!-- Last element in the array which is the count of notifications calculated server side by PHP -->                  
                console.log(notif_count);                    
                $('#count').text(notif_count);

Answer 1

使用数组索引。有关JS中的数组的更多详细信息，请查看MDN。

对于你的问题，这可行 -

var notif_count = data[1] 
//index 1 will give 2nd element, as array indexing is zero indexing.

var notif_count = data.pop();对我有用。检查FF控制台。相同的例子没有区别。

注意JSON字符串中的新行字符。

Answer 2

根据您在评论中提供的反馈进行编辑。首先需要使用JSON.parse将字符串转换为列表，然后选择索引中的最后一项：

var data = '["a","b","c"]';
data_2 = JSON.parse(data)
var notif_count = data_2[data_2.length-1];
console.log(notif_count) --> 'c'
console.log(data_2) --> ['a','b','c']

获取数组.pop（）的最后一个元素的Javascript不是函数

2 个答案: