我使用jQuery CSV(https://github.com/evanplaice/jquery-csv)将csv文件转换为jQuery对象。
以下是代码:
$.ajax({
type: "GET",
url: "/path/myfile.csv",
dataType: "text",
success: function(data) {
// once loaded, parse the file and split out into data objects
// we are using jQuery CSV to do this (https://code.google.com/p/jquery-csv/)
var data = $.csv.toObjects(data);
});
我正在将公司的bushels_per_day值相加,并希望重构我的代码以使其更紧凑。
使用这个答案:Sum values in jQuery object by key,我可以循环使用$ .each();
对象格式如下:
var data = [
"0":{
bushels_per_day: "145",
plant_city: "Decatur",
plant_company: "AGP",
},
"1":{
bushels_per_day: "125",
plant_city: "Cedar Rapids",
plant_company: "AGP",
},
"2":{
bushels_per_day: "345",
plant_city: "Ralston",
plant_company: "AGP",
},
"3":{
bushels_per_day: "55",
plant_city: "Dawson",
plant_company: "ADM",
},
"4":{
bushels_per_day: "55",
plant_city: "Dawson",
plant_company: "ADM",
},
// ... more objects
]
这是$ .each()循环:
var sumADM = 0;
var sumAGP = 0;
// var for each company
$.each(data, function (index, value) {
var capacity = parseInt(value.bushels_per_day, 10);
var company = value.plant_company.replace(/\W+/g, '_').toLowerCase();
if (company == 'adm') {
sumADM += capacity;
}
if (company == 'agp') {
sumAGP += capacity;
}
// ... and so on for each company
});
console.log(sumADM, sumAGP); // and so on.
这有效,但我怎么能重构这个,这样我就不需要每个公司的sum变量和if语句?目前,sum变量和console.log()必须在循环之外才能返回正确的总数。
有更好,更紧凑的方法吗?
答案 0 :(得分:3)
您可以将对象作为属性放在对象上:
var sums = {
ADM: 0,
AGP: 0
};
$.each(data, function (index, value) {
var capacity = parseInt(value.bushels_per_day, 10);
var company = value.plant_company.replace(/\W+/g, '_').toUpperCase(); // Note change here
sums[company] += capacity;
});
console.log(sums.ADM, sums.AGP); // and so on.
或者以循环方式输出它们:
Object.keys(sums).forEach(function(company) {
console.log(sums[company]);
});
如果公司不同,你甚至可以做懒惰的初始化:
var sums = {};
$.each(data, function (index, value) {
var capacity = parseInt(value.bushels_per_day, 10);
var company = value.plant_company.replace(/\W+/g, '_').toUpperCase();
sums[company] = (sums[company] || 0) + capacity;
});
Object.keys(sums).forEach(function(company) {
console.log(sums[company]);
});
sums[company] = (sums[company] || 0) + capacity;
行的工作方式是,如果我们之前没有见过该公司,sums[company]
将是undefined
。由于undefined
是假的,因此JavaScript curiously-powerful ||
operator会将右侧操作数值(0
)作为结果。如果我们之前看到company
并且sums[company]
是0
,那也是如此,但是没关系,0
是一个0
。所有其他值(1
等)都是真实的,因此sum[company] || 0
将是1
等等(左手操作数的值)。
附注:注意我在公司字符串上使用toUpperCase
而不是toLowerCase
,因此它们与属性匹配。