Question

我试图使用他们的ISO（cca2）代码搜索一个国家的首都。

我正在做以下事情：

 var json =   $.getJSON('Countries.json', function(data)
{
       return data;
});

var CapitalCity = getCapitalByCCA2(json, code.toString().toUpperCase());

alert(CapitalyCity);

function getCapitalByCCA2(json, code) {
   for (var i = 0; i < json.length; i++) {
                if (json[i].cca2 === code.toString().toUpperCase()) {
                    return json[i].capital;
                    console.log(json[i]);
                }
            }
    return null;
};

JSON文件的结构：

[
    {
        "name": {
            "common": "Afghanistan",
            "official": "Islamic Republic of Afghanistan",
            "native": {
                "common": "\u0627\u0641\u063a\u0627\u0646\u0633\u062a\u0627\u0646",
                "official": "\u062f \u0627\u0641\u063a\u0627\u0646\u0633\u062a\u0627\u0646 \u0627\u0633\u0644\u0627\u0645\u064a \u062c\u0645\u0647\u0648\u0631\u06cc\u062a"
            }
        },
        "tld": [".af"],
        "cca2": "AF",
        "ccn3": "004",
        "cca3": "AFG",
        "currency": ["AFN"],
        "callingCode": ["93"],
        "capital": "Kabul",
        "altSpellings": ["AF", "Af\u0121\u0101nist\u0101n"],
        "relevance": "0",
        "region": "Asia",
        "subregion": "Southern Asia",
        "nativeLanguage": "pus",
        "languages": {
            "prs": "Dari",
            "pus": "Pashto",
            "tuk": "Turkmen"
        },
        "translations": {
            "cym": "Affganistan",
            "deu": "Afghanistan",
            "fra": "Afghanistan",
            "hrv": "Afganistan",
            "ita": "Afghanistan",
            "jpn": "\u30a2\u30d5\u30ac\u30cb\u30b9\u30bf\u30f3",
            "nld": "Afghanistan",
            "rus": "\u0410\u0444\u0433\u0430\u043d\u0438\u0441\u0442\u0430\u043d",
            "spa": "Afganist\u00e1n"
        },
        "latlng": [33, 65],
        "demonym": "Afghan",
        "borders": ["IRN", "PAK", "TKM", "UZB", "TJK", "CHN"],
        "area": 652230
    },
    {
        "name": {
            "common": "\u00c5land Islands",
            "official": "\u00c5land Islands",
            "native": {
                "common": "\u00c5land",
                "official": "Landskapet \u00c5land"
            }
        },
        "tld": [".ax"],
        "cca2": "AX",
        "ccn3": "248",
        "cca3": "ALA",
        "currency": ["EUR"],
        "callingCode": ["358"],
        "capital": "Mariehamn",
        "altSpellings": ["AX", "Aaland", "Aland", "Ahvenanmaa"],
        "relevance": "0",
        "region": "Europe",
        "subregion": "Northern Europe",
        "nativeLanguage": "swe",
        "languages": {
            "swe": "Swedish"
        },
        "translations": {
            "deu": "\u00c5land",
            "fra": "\u00c5land",
            "hrv": "\u00c5landski otoci",
            "ita": "Isole Aland",
            "jpn": "\u30aa\u30fc\u30e9\u30f3\u30c9\u8af8\u5cf6",
            "nld": "\u00c5landeilanden",
            "rus": "\u0410\u043b\u0430\u043d\u0434\u0441\u043a\u0438\u0435 \u043e\u0441\u0442\u0440\u043e\u0432\u0430",
            "spa": "Alandia"
        },
        "latlng": [60.116667, 19.9],
        "demonym": "\u00c5landish",
        "borders": [],
        "area": 1580
    }

    }

]

问题在于没有获取数据。

我做错了什么？

Answer 1

您应该使用grep来过滤json，如下所示：

var returnedData = $.grep(json, function (element, index) {
    return element.cca2 === code.toString().toUpperCase();
});

returnData将包含已过滤的json的数组。

我在代码中没有看到var code的任何定义。

Answer 2

$.getJSON()无效，因为您将数据返回到变量中。相反，您需要做的是使用$.getJSON()提供回调来处理结果。尝试从成功回调中调用您的函数。

// variable to store captial city
var CapitalCity;
// The country code you are filtering on
var countryCode = '...';
$.getJSON('Countries.json', function(data) {
    CapitalCity = getCapitalByCCA2(data, countryCode);      
});

您实际上可以查看@MathieuLabrieParent提供的搜索建议，并完全摆脱您的功能。但是，我可能会更改为使用$.each()进行数组迭代，以便在找到匹配项时可以突破循环。这可能是这样的：

// variable to store captial city
var CapitalCity;
// The country code you are filtering on
var countryCode = code.toString().toUpperCase();
$.getJSON('Countries.json', function(data) {
    $.each(data, function (index, element) {
        if (element.cca2 === countryCode) {
            CapitalCity = match.capital;
            // break the loop
            return false;
        }
    }); 
});

在JSON文件中搜索。

2 个答案: