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Instead of using associative arrays (objects), what is the best way to associate two values so they are always associated and can both be accessed as separate values? Associative arrays are annoying because their order isn't guaranteed and you can't access them using indexes.
I could create two separate arrays but if I randomize their order for display their association would not match, and if they are separate in code there is a good chance I can make a mistake when recording their values, putting them in the wrong order so they don't perfectly match up.
In Javascript you can use multidimensional arrays:
var data = [
[1, 2],
[3, 4]
];
data[0][0]; // get '1'
data[0][1]; // get '2'
Also if you need to associate data in a more abstract way, ES6 has WeakMaps:
var wm = new WeakMap();
var x = document.createElement("div");
wm.set(x, {foo: 1, bar: 7});
console.log(wm.get(x).bar) // get '7' from object you associated to HTMLElement
I do not now which kind of data you should store but maybe you could try to store data in a single variable in this way:
var data = [];
data[0] = "Test" + "|" + Value;
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I want to get data from the object without for loop
this is my object
data = [{name:"A",value:[java:45,c++:50]},{name:"B",value:[java:12,c++:47]},{name:"C",value:[java:15,c++:32]}]
Expected result:
result_name = ["A","B","C"]
result_java = [45,12,15]
The structure of your array data is invalid. You wrote nested array value in square brackets yet the items are written as key-value pairs.
There is no magical way you can obtain multiple data from an array without iteration/looping. (unless you already know the indices, but this defeats the purpose of using arrays)
That said, if you meant to avoid only the "for" loops, you can:
Fix your data as below.
let data = [
{name:"A", value:{java:45,"c++":50}},
{name:"B", value:{java:12,"c++":47}},
{name:"C", value:{java:15,"c++":32}}
];
Run an alternative loop such as below.
console.log(data.map(item => item.name)); // ["A", "B", "C"]
console.log(data.map(item => item.value.java)); // [45,12,15]
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I want to create an Array from another by applying the proportionality rule.
For example:
Array1 = [15,550,76,3,400,230]
I take the maximum value from Array1 which is equal in my array 550
Now, with a function, I want to create a second array Array2 with a value equal to 10 which corresponds to 550 in the first array, like Array2 = [?,10,?,?,?,?]
I want to apply the proportionality rule function to determine the other values of Array2 to get Array2=[0.27,10,1.38,0.05,7.27,4.6]
Any help please how can I create the function with array param?
Thank you.
const array1 = [15,550,76,3,400,230]
function proportionalityRule(array){
const maxValue = Math.max(...array)
return array.map(element => (element/maxValue) * 10)
}
proportionalityRule(array1)
// (6) [0.2727272727272727, 10, 1.3818181818181818, 0.05454545454545455, 7.272727272727273, 4.181818181818182]
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business=[0:{"name":{"en":'prateek'}},1:{"name":{"ar":'rahul'}}]
How I can extract the value of en and ar from this type of the repeted object in a array
The issue with your question is that you define business as an Array with the use of square brackets, but then proceed to use key value pairs directly within the array (via the usage ":"), which is reserved for objects and not arrays. I'd recommend researching both array and object datatypes, however simply put:
let myArray = [1, 2, 3, ...];
// only stores values which can be retrieved using the values index i.e. myArray[0]
let myObj = {"key1" : "value1", "key2" : "value2"};
// values are stored against keys, and can be accessed via the key i.e. myObj.key1
I think you've confused how objects and arrays should work. My guess is that you'd be better off with this structure:
let businesses = [];
businesses.push({enName: 'prateek', arName: 'rahul'});
console.log(businesses[0], businesses[0].enName, businesses[0].arName);
This way you're using an array to hold a collection of businesses and which are represented by objects. These objects in turn have attributes for enName and arName.
I think this would be a much clearer way of structuring your issue.
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As the title suggests, how do I make a new object containing the 7 first keys of another object using JS? :) This is the structure of the object I would like to copy the data from.
{"data":[{"id":2338785,"team1":{"id":10531,"name":"Just For Fun"},"team2":{"id":10017,"name":"Rugratz"},"result":"2 - 0","event":{"name":"Mythic Cup 5","id":5148},"format":"bo3","stars":0,"date":1578279271000},....],"last_update":1578329378792}
Let's say there are 100 keys like this one, and I only want to copy the 7 first ones into a new object in JS.
Well technically, you have only 2 keys in the given Object but if you mean the data object, here's what you can do.
const MyNewObject = Object.entries(YourObject)
const results = []
and a simple for loop
MyNewObject.forEach((pair,i) => {
// for the 8th item it breaks and doesn't push it to results array
if ( i === 7 ) break;
results.push(pair)
}
OR u use slice instead :
// a little bit neater , and u call remove the empty results array above
const thisNewResult = MyNewObject.slice(0,6)
and finally the results is an array of key value pairs and you should do this code to make a new object from the results entries
const finalResults = Object.fromEntries(results)
Please notice that this may not be the Order you want since Object.Entries gives you the same order as the order of for in loop (for more info visit Elements order in a "for (… in …)" loop)
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I want to create an array of objects in which each objects has 4 values. All coming from 4 diferent arrays.The arrays are long.I have no idea on how to do it. It's pretty difficult i think, i have been looking for hours vv'.
var local=[F.C Barcelona, Real Madrid, Manchester United.....];
var away=[ Manchester City, PSG, Liverpool....];
var matchDay[2,3,4,5....];
var score=[2-0, 0-1, 2-2...];
// array to hold the objects
let arr = []
// assuming the four arrays are all the same length
// just pick one to use for the length
for(let i = 0; i < local.length; i++) {
// create a new object with the 4 fields, one from each array
// and grab the i'th entry of each array for it
let obj = {
local: local[i],
away: away[i],
matchDay: matchDay[i]
score: score[i]
};
arr.push(obj);
}
Not sure exactly what you're trying to do, but something like this would work.
> array1.map(function(item, index){
return {key1: item,
key2: array2[index],
key3: array3[index]
};
});