如何从JavaScript对象数组中获取键值对
How do I get key-value pair from array of JavaScript objects?
我有
var results = {};
我编写的代码用以下格式的数据填充结果（来自HTTPGET请求）：
({
"result":[
{
"Longitude" : "-097.722382",
"Zipcode" : "78751",
"ZipClass" : "STANDARD",
"County" : "TRAVIS",
"City" : "AUSTIN",
"State" : "TX",
"Latitude" : "+30.310606"
}
]}
)
但是，我希望结果以TRAVIS为键，然后添加另一个名为count的变量，该变量计算该县的总数。
我在访问密钥&价值观我似乎总是得undefined。如何访问密钥？
这是我的密码。从本质上讲，我要查看一堆邮政编码，只过滤掉德克萨斯州的邮政编码。
var i = 0;
var results = {};
/*
var results = {
'TRAVIS': 10,
'DALLAS': 15,
};
*/
function getValues(obj, key) {
var objects = [];
for (var i in obj) {
if (!obj.hasOwnProperty(i)) continue;
if (typeof obj[i] == 'object') {
objects = objects.concat(getValues(obj[i], key));
} else if (i == key) {
objects.push(obj[i]);
}
}
return objects;
}
callback = function(response) {
//console.log('callback('+i+')');
var str = '';
response.on('data', function (chunk) {
str += chunk;
});
response.on('end', function () {
console.log('Processing: ' + i);
// TODO: Parse JSON
str = str.replace(/[''(')]/g, "");
if(str.substring(0,1) == "{"){
JSON.parse(str);
}
if(str.substring(0,1) == "{"){
if( (str.substring(str.search("'"State'"") + 10, str.search("'"State'"") + 14)) == "'"TX'"")
{ //console.log("THIS IS FROM TEXAS ");
results[i] = str;
}
}
setTimeout(function() {
i++;
if (i >= data.length) {
console.log(results);
} else {
fetch();
}
}, 1000)
});
}
function fetch() {
//console.log('fetch('+i+')');
var options = {
host: 'gomashup.com',
path: '/json.php?fds=geo/usa/zipcode/'+ JSON.parse(data[i].zip)
};
http.request(options, callback).end();
}
fetch();
var response = ({
"result":[
{
"Longitude" : "-097.722382",
"Zipcode" : "78751",
"ZipClass" : "STANDARD",
"County" : "TRAVIS",
"City" : "AUSTIN",
"State" : "TX",
"Latitude" : "+30.310606"
}
]});
You can excess key and value this way...
console.log(response.result[0].County);
console.log(response.result[0].Zipcode);
And also add a key ......
response.result[0].count = 134;
console.log(response);
您可以使用lodash库来过滤结果。
let _ = require("lodash");
let res = {
result: [
{
"Longitude": "-097.722382",
"Zipcode": "78751",
"ZipClass": "STANDARD",
"County": "TRAVIS",
"City": "AUSTIN",
"State": "TX",
"Latitude": "+30.310606"
},
{
"Longitude": "-097.722382",
"Zipcode": "78751",
"ZipClass": "STANDARD",
"County": "TRAVIS",
"City": "AUSTIN",
"State": "TX",
"Latitude": "+30.310606"
},
{
"Longitude": "-097.722382",
"Zipcode": "78751",
"ZipClass": "STANDARD",
"County": "abc",
"City": "AUSTIN",
"State": "TX",
"Latitude": "+30.310606"
}
]
}
function test() {
let groupedResult = _.groupBy(res.result, 'County')
result = {}
_.forEach(Object.keys(groupedResult), (County)=>{
result[County] = groupedResult[County].length
})
console.log(result)
}
test();
使用类似库的下划线怎么样？可以通过groupBy和map函数实现这一点。
var grouped = _.groupBy(response.result, function(item){
return item.County;
});
var result = _.each(grouped, function(value, key, list){
return list[key] = value.length;
});
看看这个Plunker：http://plnkr.co/edit/fNOWPYBPsaNNDVX3M904
如果执行eval(%yourcode%)，它将返回一个具有一个键"result"的对象，该键指向内部只有一个值的数组-一个包含信息对的数组。因此，要访问这些密钥，您必须迭代此对象-eval(%yourcode%)['result'][0]，如下所示：
initialString = '({"result":[{"Longitude" : "-097.722382","Zipcode" : "78751","ZipClass" : "STANDARD","County" : "TRAVIS","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"}]})';
myObj = eval(initialString)['result'][0];
for (key in myObj) {
document.write(key + ': ' + myObj[key] + '<br>');
}
例如，如果您的结果对象包含许多对象，那么您应该遍历(myObj = eval(initialString)['result'])，如下所示：
initialString = '({"result":[{"Longitude" : "1","Zipcode" : "78751","ZipClass" : "STANDARD","County" : "TRAVIS","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"},{"Longitude" : "2","Zipcode" : "78751","ZipClass" : "STANDARD","County" : "TRAVIS","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"},{"Longitude" : "3","Zipcode" : "78751","ZipClass" : "STANDARD","County" : "TRAVIS","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"}]})';
myObj = eval(initialString)['result'];
myObj.forEach(function(infoItem,index) {
document.write('Item #' + (index+1) + "<br>");
for (key in infoItem) {
document.write(' ' + key + ': ' + infoItem[key] + '<br>');
}
});
哦，如果你想创建一个包含country作为关键字和zipcode作为值的"result"对象，你可以这样做：
// in this example `myObj` has 3 objects inside itself
// we iterate through each and select values that we need
var initialString = '({"result":[{"Longitude" : "1","Zipcode" : "78751","ZipClass" : "STANDARD","County" : "TRAVIS","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"},{"Longitude" : "2","Zipcode" : "37465","ZipClass" : "STANDARD","County" : "SOMECOUNTY","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"},{"Longitude" : "3","Zipcode" : "90210","ZipClass" : "STANDARD","County" : "MYBELOVEDCOUNTY","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"}]})',
result = {};
myObj = eval(initialString)['result'];
myObj.forEach(function(infoItem,index) {
// here we create entries inside 'result' object
// using county values as keys
result[infoItem['County']] = infoItem['Zipcode'];
});
document.write(JSON.stringify(result,null,'<br>'));
对不起，我终于得到了你需要的）看：
// in this example `myObj` has 4 objects inside itself
// we iterate through each and select values that we need
var initialString = '({"result":[{"Longitude" : "1","Zipcode" : "78751","ZipClass" : "STANDARD","County" : "TRAVIS","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"},{"Longitude" : "2","Zipcode" : "37465","ZipClass" : "STANDARD","County" : "SOMECOUNTY","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"},{"Longitude" : "3","Zipcode" : "90210","ZipClass" : "STANDARD","County" : "MYBELOVEDCOUNTY","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"},{"Longitude" : "4","Zipcode" : "90210","ZipClass" : "STANDARD","County" : "MYBELOVEDCOUNTY","City" : "AUSTIN","State" : "TX","Latitude" : "+30.310606"}]})',
result = {};
myObj = eval(initialString)['result'];
myObj.forEach(function(infoItem,index) {
// here we create entries inside 'result' object
// using county value as a keys
// first we check if an entry with current key exists
if (result[infoItem['County']]) {
// if yes, just increment it
result[infoItem['County']]++;
} else {
// if no, make it equal to 1
result[infoItem['County']] = 1;
}
});
document.write(JSON.stringify(result,null,'<br>'));由于您使用nodejs，因此可以安装字符串存储npm模块。它将它转换为一个数组，并且可以很容易地使用这些值。更多详细信息请点击此处。https://www.npmjs.com/package/stringstore
相关文章：
- 正在数组中存储键值对
- 如何将新的键/值对元素添加到现有数组
- 从 JSON 获取键值对而不使用 .(DOT） 在 Java 脚本或 jquery 中
- 从字符串javascript中获取键值对
- 如何在Acrobat中使用javascript获取PDF表单字段的所有键值对
- 如何获取对象中的键值对列表
- 从对象的 JSON 数组中获取键值对
- 从键值对的值中获取键值
- Node JS从header中获取键值对
- 如何从具有键/值对对象的数组中获取值
- 如何获取对象中唯一的键值对的值
- 使用jQuery循环并获取JSON数组的键/值对
- 如何从json数据中获取特定的键值对并存储在节点js中的变量中
- 如何从JavaScript对象数组中获取键值对
- 访问JSON对象以获取Resource Bundle键/值对
- 从键值对中获取 json 值，而无需在 meteor 中传递键
- 如何从一组标记中获取键值对
- 如何从键值对列表中获取值
- 如何在键值对中获取输入的名称和值
- 使用jQuery获取JSON中的键/值对中的键名
