Question

拥有JSON字符串（缩短）：

{"line_array":[{"short":"[common]","long":"undefined"},{"short":"_YES","long":"Yes"},{"short":"_NO","long":"No"},{"short":"_NOT","long":"Not "},{"short":"_SEARCH","long":"Search"},{"short":"_GO","long":"Go"}]}

我希望能够根据“短”值调用一个返回“long”值的函数：

喜欢：

var test= 'Say '+get_value("_YES");

我该怎么做？

试过：

function f_lang(short_string) {
    var obj = json_string;
    var arr = [];
    json = JSON.stringify(eval('(' + obj + ')')); //convert to json string
    arr = $.parseJSON(json); //convert to javascript array

    return arr['line_array'][short_string];
}

没有运气

Answer 1

使用Array#find查找包含短值的对象。请注意，IE不支持Array#find。因此，如果您需要IE支持和/或您正在进行大量此类转换，您应该使用字典方法。

＆＃13;

var str = '{"line_array":[{"short":"[common]","long":"undefined"},{"short":"_YES","long":"Yes"},{"short":"_NO","long":"No"},{"short":"_NOT","long":"Not "},{"short":"_SEARCH","long":"Search"},{"short":"_GO","long":"Go"}]}';

var terms = JSON.parse(str);

function get_value(short) {
   var term = terms.line_array.find(function(o) {
     return o.short === short;
   });
  
  //in case the term isn't found, we'll prevent term.long from throwing an error
  return term && term.long;
}

var result = get_value('_YES');

console.log(result);

＆＃13;

使用字典对象

使用Array#reduce创建字典并使用它：

＆＃13;

var str = '{"line_array":[{"short":"[common]","long":"undefined"},{"short":"_YES","long":"Yes"},{"short":"_NO","long":"No"},{"short":"_NOT","long":"Not "},{"short":"_SEARCH","long":"Search"},{"short":"_GO","long":"Go"}]}';

var terms = JSON.parse(str);

var termsDictionary = terms.line_array.reduce(function(d, t) {
  d[t.short] = t.long;
  return d;
}, Object.create(null));

function get_value(short) {
  return termsDictionary[short]; // you can use this expression without the function of course
}

var result = get_value('_YES');

console.log(result);

＆＃13;

Answer 2

使用正确解析的JSON，您可以使用Array#find，ES6功能。

function getValue(short_string) {
    return (object.line_array.find(a => a.short === short_string) || {}).long;
}

var json_string = '{"line_array":[{"short":"[common]","long":"undefined"},{"short":"_YES","long":"Yes"},{"short":"_NO","long":"No"},{"short":"_NOT","long":"Not "},{"short":"_SEARCH","long":"Search"},{"short":"_GO","long":"Go"}]}',
    object = JSON.parse(json_string),
    test= 'Say '+getValue("_YES");

console.log(test);

ES5与Array#some

function getValue(short_string) {
    var value;
    object.line_array.some(function (a) { 
        if (a.short === short_string) {
            value = a.long;
            return true;
        }
    });
    return value;
}

var json_string = '{"line_array":[{"short":"[common]","long":"undefined"},{"short":"_YES","long":"Yes"},{"short":"_NO","long":"No"},{"short":"_NOT","long":"Not "},{"short":"_SEARCH","long":"Search"},{"short":"_GO","long":"Go"}]}',
    object = JSON.parse(json_string),
    test= 'Say '+getValue("_YES");

console.log(test);

Answer 3

另一种选择：

function f_lang(short_string) {
    var obj = {"line_array":[{"short":"[common]","long":"undefined"},{"short":"_YES","long":"Yes"},{"short":"_NO","long":"No"},{"short":"_NOT","long":"Not "},{"short":"_SEARCH","long":"Search"},{"short":"_GO","long":"Go"}]};
    for (var i = 0; i < obj['line_array'].length; i++) {
      if (obj['line_array'][i]['short'] == short_string) {
        return obj['line_array'][i]['long'];
      };
    }
}

console.log('Say ' + f_lang("_YES"));

Answer 4

您可以使用Array.Filter

var haystack = {"line_array":[{"short":"[common]","long":"undefined"},{"short":"_YES","long":"Yes"},{"short":"_NO","long":"No"},{"short":"_NOT","long":"Not "},{"short":"_SEARCH","long":"Search"},{"short":"_GO","long":"Go"}]}

console.log(haystack.line_array.filter(e => e.short === '_YES').long)

Answer 5

请尝试以下代码

override func isApplicableToList(list: [ShoppingItem]) -> Bool {
    //should return true if a dicount can be applied based on the supplied list of product ids (i.e. a product must be matched to an offer)

    for item in list {
        if applicableProductIds.contains(item.productId) {
            return true
        }
    }

    // didn't find one       
    return false
}

javascript json数组输出

5 个答案: