如何用jQuery从json对象中获取一些值?

I have this json file and I converted it in json object:

我有这个json文件，我把它转换成json对象:

[
  {
    "id": "1",
    "nome": "erwrw",
    "cognome": "sdsfdfs",
    "CF": "qwert",
    "eta": "27",
    "sesso": "uomo",
    "indirizzo": "qwerrt",
    "luogo": "wewrw",
    "provincia": "ewrewrw",
    "citta": "erwrwr",
    "comune": "ewrewrw"
  },

  {
    "id": "2",
    "nome": "mario",
    "cognome": "rossi",
    "CF": "MRSI4343242",
    "eta": "35",
    "sesso": "uomo",
    "indirizzo": "via rossi 10",
    "luogo": "bergamo",
    "provincia": "bergamo",
    "citta": "bergamo",
    "comune": "bergamo"
  }
]

With ajax I can get and print all the keys and values in a html file:

使用ajax，我可以在html文件中获取并打印所有的键和值:

function getData()  {
    var container = $('div.container');

    console.log("container",container);
    $.ajax({
        type: 'GET',
        url: 'data/persona1.json',
        dataType: 'json',
        success:function(data){
            console.log(data);
            console.log(data[0].nome);

            $.each(data, function(index, item) {
                $.each(item, function(key, value){
                    container.append(key + ' : ' + value + '<br/>');
                });
                container.append('<br/><br/>');
            });
        },

});
};

BUT How can I do to print just "nome", "cognome", "citta" of every object?

但是我怎么能只打印“nome”、“cognome”、“citta”的每个对象呢?

5 个解决方案

#1

If you know the names of the properties you want to retrieve you can access them directly by name without the loop, try this:

如果您知道要检索的属性的名称，您可以不通过循环直接通过名称访问它们，请尝试以下操作:

var data = [{
    "id": "1",
    "nome": "erwrw",
    "cognome": "sdsfdfs",
    "CF": "qwert",
    "eta": "27",
    "sesso": "uomo",
    "indirizzo": "qwerrt",
    "luogo": "wewrw",
    "provincia": "ewrewrw",
    "citta": "erwrwr",
    "comune": "ewrewrw"
}, {
    "id": "2",
    "nome": "mario",
    "cognome": "rossi",
    "CF": "MRSI4343242",
    "eta": "35",
    "sesso": "uomo",
    "indirizzo": "via rossi 10",
    "luogo": "bergamo",
    "provincia": "bergamo",
    "citta": "bergamo",
    "comune": "bergamo"
}]

var container = $('div.container');
$.each(data, function(index, item) {
    container.append('Nome : ' + item.nome + '<br/>Cognome : ' + item.cognome + '<br/>Citta : ' + item.citte + '<br/><br/><br/>');
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<div class="container"></div>

#2

Remove the inner each loop. Then print the keys you want:

删除内部每个循环。然后打印你想要的密钥:

$.each(data, function(index, item) {
    container.append('nome : ' + item['nome']+ '<br/>');
    container.append('cognome : ' + item['cognome']+ '<br/>');
    container.append('citta: ' + item['citta']+ '<br/>');
    container.append('<br/><br/>');
});

#3

Just put an if condition in your $.each()

在$.each()中输入if条件

var data = [
  {
    "id": "1",
    "nome": "erwrw",
    "cognome": "sdsfdfs",
    "CF": "qwert",
    "eta": "27",
    "sesso": "uomo",
    "indirizzo": "qwerrt",
    "luogo": "wewrw",
    "provincia": "ewrewrw",
    "citta": "erwrwr",
    "comune": "ewrewrw"
  },

  {
    "id": "2",
    "nome": "mario",
    "cognome": "rossi",
    "CF": "MRSI4343242",
    "eta": "35",
    "sesso": "uomo",
    "indirizzo": "via rossi 10",
    "luogo": "bergamo",
    "provincia": "bergamo",
    "citta": "bergamo",
    "comune": "bergamo"
  }
]


$.each(data, function(index, item) {
                console.log(item)
                $.each(item, function(key, value){
                    if(key == "nome" || key == "cognome" || key == "citta")
                    $('.container').append(key + ' : ' + value + '<br/>');
                });
                $('.container').append('<br/><br/>');
            });

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

#4

The fastest way - create an array with keys you need and check in the loop if key is in the array.

最快的方法——用你需要的键创建一个数组，如果键在数组中，就在循环中进行检查。

fields = ['nome','cognome','citta'];
...
if ($.inArray(key, fields)){
    ...
}

This way it will be a lot easier to modify the fields than by adding if/else or each name separately.

这样，修改字段要比分别添加if/else或每个名称容易得多。

#5

$.each is very slow. if you have a lot of data you can use for loop for more performance.

美元。每个速度非常慢。如果您有很多数据，您可以使用for循环获得更多的性能。

link with test performance : link

链接到测试性能:链接

var data = [{
    "id": "1",
    "nome": "erwrw",
    "cognome": "sdsfdfs",
    "CF": "qwert",
    "eta": "27",
    "sesso": "uomo",
    "indirizzo": "qwerrt",
    "luogo": "wewrw",
    "provincia": "ewrewrw",
    "citta": "erwrwr",
    "comune": "ewrewrw"
}, {
    "id": "2",
    "nome": "mario",
    "cognome": "rossi",
    "CF": "MRSI4343242",
    "eta": "35",
    "sesso": "uomo",
    "indirizzo": "via rossi 10",
    "luogo": "bergamo",
    "provincia": "bergamo",
    "citta": "bergamo",
    "comune": "bergamo"
}]

var container = $('div.container');
for(var t=0;t<data.length;t++){
     container.append('Nome : ' + data[t].nome + '<br/>Cognome : ' + data[t].cognome + '<br/>Citta : ' + data[t].citte + '<br/><br/><br/>');
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<div class="container"></div>