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Javascript Key/Value Pairing with Arrays

I am trying to wrap my head around how I might accomplish something like this, structurally:
var keywordDataProducts =
[
{"keyword" : "keyword1", "list" : [ "DP1", "DP2" ] },
{"keyword" : "keyword2", "list" : [ "DP1" ] }
];
But of course, without the values being hard coded. For instance, we currently loop through all the DP values (DP1, DP2, DP3, etc..) - which all have 0-M keywords. I'm trying to create an inverse lookup of that, where you can get all DPs that use a particular keyword. I have code that uses the structure above perfectly, but I just need the data to get populated more dynamically.
Do I initialize the var keywordDataProducts = []; declaration with anything in it, or define the structure of it having a keyword and a list (which is an array)? Or do you leave it as an array with nothing about it, and define that when you're adding items?
I've heard associative arrays can be used for a situation like this, but I'm not quite wrapping my head around that at the moment. I've also seen objects with {} usages, but there is no push there and I need an array of keywords, which also contains arrays of DPs (list). Thoughts?

You would do something like this, but you didn't clearly describe what the input look like and what output you're looking for.
function fn (input) {
var ouput = {};
input.forEach( function (DP) {
for (prop in DP) {
if (DP.hasOwnProperty(prop) {
if (output[prop]) {
output[prop].push(DP);
} else {
output[prop] = [DP];
}
}
}
});
return output;
}
This takes this kind of input
[{"alpha":...}, {"beta":..., "delta":...}, {"alpha":..., "gamma":...}]
and returns
{"alpha":[{"alpha":...}, {"alpha":..., "gamma":...}]}, "beta":{"beta":..., "delta":...}, "delta":{"beta":..., "delta":...}, "gamma":{"alpha":..., "gamma":...}}

I don't know how you want your output so I just made an object with each keyword as its own key for the DP values.
var data = [{dp: "dp1", keys: ["key1", "key2", "key3"]}, {dp: "dp2", keys: ["key1", "key2", "key3"]}, {dp: "dp3", keys: ["key1", "key2", "key3"]},];
function keyWordArray(arr) {
var newObj = {};
arr.forEach((obj) => {
obj.keys.forEach((keyVal) => {
if(newObj.hasOwnProperty(keyVal)){
newObj[keyVal].dp.push(obj.dp);
} else {
newObj[keyVal] = {dp:[obj.dp],};
}
});
});
return newObj;
}
document.getElementById("data").innerHTML = JSON.stringify(keyWordArray(data));
<div id="data">
</div>

You can treat objects as associative arrays, and you don't have to use "push" to add a new element.
// Create your object like this
var keywordDataProducts =
{
"keyword1" : { "list" : [ "DP1", "DP2"] },
"keyword2" : { "list" : [ "DP1" ] }
};
// Treat it like an associative array
var keyword1 = keywordDataProducts["keyword1"];
alert("keyword1 = " + keyword1.list.join(", "));
// Add to it like this
keywordDataProducts["keyword3"] = { "list" : ["DP3", "DP4"] };
// See the new object includes your new keyword
alert(JSON.stringify(keywordDataProducts));
// To iterate the keys of your object, you can do something like this
for(var item in keywordDataProducts)
{
if(keywordDataProducts.hasOwnProperty(item))
{
alert(item);
}
}
You can see the fiddle here;
https://jsfiddle.net/gksjtwr6/2/

Looping through JSON returning values

I've json which looks little complex array of json, I want to parse "1238630400000" and "16.10", like this I need all the values. I'm not getting how we can parse all these values.
This is the code I've tried but no luck:
for (var key in myJSON.Stocks) {
alert(myJSON.Stocks[key].stockPrice);
}
var myJSON = {
"Stocks": {
"stockPrice": [
[1238630400000, 16.10],
[1238716800000, 16.57],
[1238976000000, 16.92],
[1239062400000, 16.43],
[1239148800000, 16.62],
[1239235200000, 17.08],
[1239580800000, 17.17],
[1239667200000, 16.90],
[1239753600000, 16.81],
[1239840000000, 17.35],
[1239926400000, 17.63],
[1241049600000, 17.98]
]
}
}
Can someone help how can i get all these values?

You can get the values by doing a simple forEach on the stockPrice array
myJSON.Stocks.stockPrice.forEach(function(data) { console.log(data[0], data[1]); });

Here is the simplest way:
var csv = myJSON.Stocks.stockPrice.map((o)=>o.join()).join();
console.log(csv);

Access the nested value in JSON without looping through it

This is my JSON, I want to directly get the zipCodes values from the JSON without looping through the JSON. How can I do it?
countries:[
{
name:'India',
states:[{
name:'Orissa',
cities:[{
name:'Sambalpur',
zipCodes:{'768019','768020'}
}]
}]
}
]

I think you are looking for
countries[0].states[0].cities[0].zipCodes
Please note, this works for the above JSON as there is only 1 country in countries array and same as for states and cities. However, if there are more than 1 country, state or city then, you will have to iterate to extract information until and unless you know the exact index.

As this is not an associative array, your option is only to use indexes like this:
countries[x].states[y].cities[0].zipCodes
Where x would be each representation of state in your array, in case, of course, that you have more than one.
Similarly y would be each state in each state in each country, in case you have more of those and you can do the same for cities if you need to.
EDIT:
Here's how you can iterate the array:
for(var c in countries)
{
var name = countries[c].name;
if (name === "CountryIAmLookingFor")
{
var statesList = countries[c].states;
for (var s in statesList)
{
var stateName = statesList[s].name;
.....
}
}
}
You can keep iterating until you find the country, state, and city you need, then extract the zipCodes from there as shown in the previous code snippet.

Without "looping"
You can do this crazy trick (not saying this is the best way, but this way you aren't looping through the JSON):
var myData = { 'Put Your Data': 'HERE' };
function getCodes(name, data) {
var sv = data.match(new RegExp(name+'([\\S\\s]*?}][\\S\\s]*?}])'))[1].match(/zipCodes":\[(.*?)\]/g), r = [];
sv.forEach(function (item) {
item.match(/\d+/g).forEach(function (sub) {
r.push(+sub);
});
});
return r;
}
getCodes('India', JSON.stringify(myData));
If your data is already string, then you don't need the JSON.stringify. The forEach you see isn't actually "looping" through the JSON. It's already extracted the zip codes and the code just adds the zip codes to the array. . This line:
var sv = JSON.stringify(data).match(new RegExp(name+'([\\S\\s]*?}][\\S\\s]*?}])'))[1].match(/zipCodes":\[(.*?)\]/g), r = [];
is what grabs the zip codes, it gets something like:
["zipCodes":["768019","768020"]"]
The next line:
item.match(/\d+/g)
will grab the numbers outputting something like:
["768019", "768020"]
The loop just adds the zip-codes to another array
With looping
You're better off looping through the JSON:
var myData = {}, // Your data
zips = [];
myData.countries.forEach(function(i) {
if (i.name === 'India') {
i.states.forEach(function(j) {
j.cities.forEach(function(l) {
l.zipCodes.forEach(function(m) {
zips.push(m);
});
});
});
}
});
//use "zips" array
PERFORMANCE AND SPEED TESTS
After testing copying an array about 500MB (half a gig) took about 30 seconds. That's a lot. Considering an extremely large JSON would be about ~5MB, looping through a little over 5MB of JSON takes about 0.14 seconds. You should never worry about speed.

Here's my "trick" for avoiding explicit iteration. Let JSON.parse or JSON.stringify do the work for you. If your JSON is in string form, try this:
var array = [];
JSON.parse(jsonString, function (key, value) {
if (key === "zipCodes") {
array = array.concat(value);
}
return value;
});
console.log(array); // all your zipCodes

Suppose your Json is like
countries =[
{
name:'India',
states:[{
name:'Orissa',
cities:[{
name:'Sambalpur',
zipCodes:768019768020
}]
},{
name:'mumbai',
cities:[{
name:'rea',
zipCodes:324243
}]
}]
}
]
So now we use MAP it will give you ZipCode of every cities
countries.map(function(s){
s.states.map(function(c){
c.cities.map(function(z){
console.log(z.zipCodes)
})
})
})
OR
If you use return statement then it will give you 2 array with two zip code as per over JSON
var finalOP = countries.map(function(s){
var Stalist = s.states.map(function(c){
var zip = c.cities.map(function(z){
return z.zipCodes
})
return zip
})
return Stalist
})
console.log(finalOP)

Get json data from a file

I wan't to get data from a json file without knowing exacly where the data is:
I have this json
var names= [
{
"category":"category1" ,
"name1":"david",
"name2":"jhon",
"name3":"peter"
},
{
"category":"category2" ,
"name1":"Smith" ,
"name2":"Anna",
}
]
suppose i have a string variable:
var str='category2';
how can i get category2.name1 using the variable?
I don't want to use names[1].name1 because i don't know whats in str and i want to avoid using for loop.

There are some build-in functions that may help you. For example:
var matchingElements = names.filter(function(object, index, array) {
return object.category == str;
});
What you're looking for will always be in matchingElements[0].name1 if matchingElements.length > 0.

Looping to Parse JSON Data

Description and Goal:
Essentially data is constantly generated every 2 minutes into JSON data. What I need to do is retrieve the information from the supplied JSON data. The data will changed constantly. Once the information is parsed it needs to be captured into variables that can be used in other functions.
What I am stuck in is trying to figure out how to create a function with a loop that reassigns all of the data to stored variables that can later be used in functions.
Example information:
var json = {"data":
{"shop":[
{
"carID":"7",
"Garage":"7",
"Mechanic":"Michael Jamison",
"notificationsType":"repair",
"notificationsDesc":"Blown Head gasket and two rail mounts",
"notificationsDate":07/22/2011,
"notificationsTime":"00:02:18"
},
{
"CarID":"8",
"Garage":"7",
"Mechanic":"Tom Bennett",
"notificationsType":"event",
"notifications":"blown engine, 2 tires, and safety inspection",
"notificationsDate":"16 April 2008",
"notificationsTime":"08:26:24"
}
]
}};
function GetInformationToReassign(){
var i;
for(i=0; i<json.data.shop.length; i++)
{
//Then the data is looped, stored into multi-dimensional arrays that can be indexed.
}
}
So the ending result needs to be like this:
shop[0]={7,7,"Michael Jamison",repair,"Blown Head gasket and two rail mounts", 07/22/2011,00:02:18 }
shop[1]={}

You can loop through your JSON string using the following code,
var JSONstring=[{"key1":"value1","key2":"value2"},{"key3":"value3"}];
for(var i=0;i<JSONstring.length;i++){
var obj = JSONstring[i];
for(var key in obj){
var attrName = key;
var attrValue = obj[key];
//based on the result create as you need
}
}
Hope this helps...

It sounds to me like you want to extract the data in the "shop" property of the JSON object so that you can easily reference all of the shop's items. Here is an example:
var json =
{
"data":
{"shop":
[
{"itemName":"car", "price":30000},
{"itemName":"wheel", "price":500}
]
}
},
inventory = [];
// Map the shop's inventory to our inventory array.
for (var i = 0, j = json.data.shop.length; i < j; i += 1) {
inventory[i] = json.data.shop[i];
}
// Example of using our inventory array
console.log( inventory[0].itemName + " has a price of $" + inventory[0].price);

Well, your output example is not possible. You have what is a list of things, but you're using object syntax.
What would instead make sense if you really want those items in a list format instead of key-value pairs would be this:
shop[0]=[7,7,"Michael Jamison",repair,"Blown Head gasket and two rail mounts", 07/22/2011,00:02:18]
For looping through properties in an object you can use something like this:
var properties = Array();
for (var propertyName in theObject) {
// Check if it’s NOT a function
if (!(theObject[propertyName] instanceof Function)) {
properties.push(propertyName);
}
}
Honestly though, I'm not really sure why you'd want to put it in a different format. The json data already is about as good as it gets, you can do shop[0]["carID"] to get the data in that field.