constructing two dimensional array dynamically - javascript

I have some values in JavaScript array as shown
var sampledata = {10,20,30,40};// these values would come from database later
I want to create a two dimensional array with these values.
I want to create a array as
var newData = [[0,10],[1,20],[2,30],[3,40]]

Pure JavaScript:
var newData = [];
var sampledata = [10,20,30,40];
for (var i = 0; i < sampledata.length; i++) {
newData.push([i, sampledata[i]]);
}
Using higher-order functions:
var newData = sampledata.map(function(el, i) {
return [i, el];
})

if sampledata is an array
var sampledata = [10,20,30,40]
var newData = []
jQuery.each(sampledata,function(i,data){newData.push([i,data])})

Related

how to transpose 2d array using javascript [duplicate]

This question already has answers here:
Transposing a 2D-array in JavaScript
(25 answers)
Closed 2 years ago.
I have an array comprising of the following data and I am using javascript to process the data
Portfolio, Value
["SFT_DEA_LXD", 17841.17]
["SFT_DEA_LXD", 69373.28]
["SFT_DEA_LXD", 28279.65]
["SFT_ISA_LXD", 10082.31]
I have run a following code to summate the values and group by Portfolio
function groupBy(array, groups, value) {
var result = [],
hash = Object.create(null);
array.forEach(function (a) {
var keys = groups.map(function (i) { return a[i] }),
key = keys.join('|');
if (!hash[key]) {
hash[key] = keys.concat(0);
result.push(hash[key]);
}
hash[key][hash[key].length - 1] += +a[value];
});
return result;
}
result = groupBy(testArray, [0], 1);
testArray is
["SFT_DEA_LXD", 115494.1]
["SFT_ISA_LXD", 10082.31]
and I need to transpose the data to the following format
["SFT_DEA_LXD", "SFT_ISA_LXD"]
[115494.1, 10082.31]
Can you advise how I can change the array to the above format to pass the data to highcharts, with thanks.
Many Thanks for any help
Colin
const testArray = [["SFT_DEA_LXD", 115494.1],
["SFT_ISA_LXD", 10082.31]];
const newArray = [];
const newArray1 = [];
testArray.forEach(item => {
newArray.push(item[0]);
newArray1.push(item[1]);
});
const result = [newArray, newArray1];
I don't understand what exactly you want to do but for transposing array its very simple and you can do it with a function or script like this
let transpose = function(arr){
let m = arr.length;
let n = arr[0].length;
let f = [];
let t = [];
for (let j=0;j<n; j++){
t = [];
for (let i=0;i<m; i++){
t.push(arr[i][j]);
}
f.push(t);
}
return f;
}
let a = [["test1",125.1] , ["test2",542.2],["test3",2.2]];
let b = transpose(a);
console.log(a);
console.log(b);
const portfolios = testData.map(([portfolio]) => portfolio);
const values = testData.map(([, value]) => value);
It's as simple as that.
'use strict';
const testData = [
["SFT_DEA_LXD", 115494.1],
["SFT_ISA_LXD", 10082.31]
];
const portfolios = testData.map(([portfolio]) => portfolio);
const values = testData.map(([, value]) => value);
console.log(portfolios); [ 'SFT_DEA_LXD', 'SFT_ISA_LXD' ]
console.log(values); [ 115494.1, 10082.31 ]

How to create key value pair using two arrays in JavaScript?

I have two arrays, keys and commonkeys.
I want to create a key-value pair using these two arrays and the output should be like langKeys.
How to do that?
This is array one:
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT']
This is array two:
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*']
This is the output I need:
var langKeys = {
'en-*': 'en_US',
'es-*': 'es_ES',
'pt-*': 'pt_PT',
'fr-*': 'fr_FR',
'de-*': 'de_DE',
'ja-*': 'ja_JP',
'it-*': 'it_IT',
'*': 'en_US'
};
You can use map() function on one array and create your objects
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT'];
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*'];
var output = keys.map(function(obj,index){
var myobj = {};
myobj[commonKeys[index]] = obj;
return myobj;
});
console.log(output);
JavaScript is a very versatile language, so it is possible to do what you want in a number of ways. You could use a basic loop to iterate through the arrays, like this:
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT']
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*']
var i;
var currentKey;
var currentVal;
var result = {}
for (i = 0; i < keys.length; i++) {
currentKey = commonKeys[i];
currentVal = keys[i];
result[currentKey] = currentVal;
}
This example will work in all browsers.
ES6 update:
let commonKeys = ['en-*', 'es-*', 'pt-*', 'fr-*', 'de-*', 'ja-*', 'it-*', '*'];
let keys = ['en_US', 'es_ES', 'pt_PT', 'fr_FR', 'de_DE', 'ja_JP', 'it_IT', 'en_US'];
let zipArrays = (keysArray, valuesArray) => Object.fromEntries(keysArray.map((value, index) => [value, valuesArray[index]]));
let langKeys = zipArrays(commonKeys, keys);
console.log(langKeys);
// let langKeys = Object.fromEntries(commonKeys.map((val, ind) => [val, keys[ind]]));
What you want to achieve is to create an object from two arrays. The first array contains the values and the second array contains the properties names of the object.
As in javascript you can create new properties with variales, e.g.
objectName[expression] = value; // x = "age"; person[x] = 18,
you can simply do this:
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT'];
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*'];
var langKeys = {};
var i;
for (i=0; i < keys.length; i++) {
langKeys[commonKeys[i]] = keys[i];
}
EDIT
This will work only if both arrays have the same size (actually if keys is smaller or same size than commonKeys).
For the last element of langKeys in your example, you will have to add it manually after the loop.
What you wanted to achieve was maybe something more complicated, but then there is missing information in your question.
Try this may be it helps.
var langKeys = {};
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT']
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*']
function createArray(element, index, array) {
langKeys[element]= keys[index];
if(!keys[index]){
langKeys[element]= keys[index-(commonKeys.length-1)];
}
}
commonKeys.forEach(createArray);
console.info(langKeys);
Use a for loop to iterate through both of the arrays, and assign one to the other using array[i] where i is a variable representing the index position of the value.
var keys = ['en_US', 'es_ES', 'pt_PT', 'fr_FR', 'de_DE', 'ja_JP', 'it_IT'];
var commonKeys = ['en-*', 'es-*', 'pt-*', 'fr-*', 'de-*', 'ja-*', 'it-*', '*'];
var langKeys = {};
for (var i = 0; i < keys.length; i++) {
var commonkey = commonKeys[i];
langKeys[commonkey] = keys[i];
}
console.log(JSON.stringify(langKeys));
let keys = ['en_US', 'es_ES', 'pt_PT', 'fr_FR', 'de_DE', 'ja_JP', 'it_IT'];
let commonKeys = ['en-*', 'es-*', 'pt-*', 'fr-*', 'de-*', 'ja-*', 'it-*', '*'];
// declaration of empty object where we'll store the key:value
let result = {};
// iteration over first array to pick up the index number
for (let i in keys) {
// for educational purposes, showing the number stored in i (index)
console.log(`index number: ${i}`);
// filling the object with every element indicated by the index
// objects works in the basis of key:value so first position of the index(i)
// will be filled with the first position of the first array (keys) and the second array (commonKeys) and so on.
result[keys[i]] = commonKeys[i];
// keep in mind that for in will iterate through the whole array length
}
console.log(result);

array object manipulation to create new object

var actual = [
{"country":"UK","month":"JAN","SR":"John P","AC":"24","PR":"2","TR":1240},
{"country":"AUSTRIA","month":"JAN","SR":"Brad P","AC":"64","PR":"12","TR":1700},
{"country":"ITALY","month":"JAN","SR":"Gim P","AC":"21","PR":"5","TR":900},
{"country":"UK","month":"FEB","SR":"John P","AC":"14","PR":"4","TR":540},
{"country":"AUSTRIA","month":"FEB","SR":"Brad P","AC":"24","PR":"12","TR":1700},
{"country":"ITALY","month":"FEB","SR":"Gim P","AC":"22","PR":"3","TR":600},
{"country":"UK","month":"MAR","SR":"John P","AC":"56","PR":"2","TR":1440},
{"country":"AUSTRIA","month":"MAR","SR":"Brad P","AC":"24","PR":"12","TR":700},
{"country":"ITALY","month":"MAR","SR":"Gim P","AC":"51","PR":"5","TR":200}
];
var expect = [
{month:"JAN",val: {"UK":"24","AUSTRIA":"64","ITALY":"21"}},
{month:"FEB",val: {"UK":"14","AUSTRIA":"24","ITALY":"22"}},
{month:"MAR",val: {"UK":"56","AUSTRIA":"24","ITALY":"51"}}
];
I have array of objects which i need to reshape for one other work. need some manipulation which will convert by one function. I have created plunker https://jsbin.com/himawakaju/edit?html,js,console,output
Main factors are Month, Country and its "AC" value.
Loop through, make an object and than loop through to make your array
var actual = [
{"country":"UK","month":"JAN","SR":"John P","AC":"24","PR":"2","TR":1240},
{"country":"AUSTRIA","month":"JAN","SR":"Brad P","AC":"64","PR":"12","TR":1700},
{"country":"ITALY","month":"JAN","SR":"Gim P","AC":"21","PR":"5","TR":900},
{"country":"UK","month":"FEB","SR":"John P","AC":"14","PR":"4","TR":540},
{"country":"AUSTRIA","month":"FEB","SR":"Brad P","AC":"24","PR":"12","TR":1700},
{"country":"ITALY","month":"FEB","SR":"Gim P","AC":"22","PR":"3","TR":600},
{"country":"UK","month":"MAR","SR":"John P","AC":"56","PR":"2","TR":1440},
{"country":"AUSTRIA","month":"MAR","SR":"Brad P","AC":"24","PR":"12","TR":700},
{"country":"ITALY","month":"MAR","SR":"Gim P","AC":"51","PR":"5","TR":200}
];
var outTemp = {};
actual.forEach(function(obj){ //loop through array
//see if we saw the month already, if not create it
if(!outTemp[obj.month]) outTemp[obj.month] = { month : obj.month, val: {} };
outTemp[obj.month].val[obj.country] = obj.AC; //add the country with value
});
var expected = []; //convert the object to the array format that was expected
for (var p in outTemp) {
expected.push(outTemp[p]);
}
console.log(expected);
Iterate through array and create new list
var actual = [
{"country":"UK","month":"JAN","SR":"John P","AC":"24","PR":"2","TR":1240},
{"country":"AUSTRIA","month":"JAN","SR":"Brad P","AC":"64","PR":"12","TR":1700},
{"country":"ITALY","month":"JAN","SR":"Gim P","AC":"21","PR":"5","TR":900},
{"country":"UK","month":"FEB","SR":"John P","AC":"14","PR":"4","TR":540},
{"country":"AUSTRIA","month":"FEB","SR":"Brad P","AC":"24","PR":"12","TR":1700},
{"country":"ITALY","month":"FEB","SR":"Gim P","AC":"22","PR":"3","TR":600},
{"country":"UK","month":"MAR","SR":"John P","AC":"56","PR":"2","TR":1440},
{"country":"AUSTRIA","month":"MAR","SR":"Brad P","AC":"24","PR":"12","TR":700},
{"country":"ITALY","month":"MAR","SR":"Gim P","AC":"51","PR":"5","TR":200}
];
var newList =[], val;
for(var i=0; i < actual.length; i+=3){
val = {};
val[actual[i].country] = actual[i]["AC"];
val[actual[i+1].country] = actual[i+1]["AC"];
val[actual[i+2].country] = actual[i+2]["AC"];
newList.push({month: actual[i].month, val:val})
}
document.body.innerHTML = JSON.stringify(newList);
This is the correct code... as above solution will help you if there are 3 rows and these will be in same sequnece.
Here is perfect solution :
var actual = [
{"country":"UK","month":"JAN","SR":"John P","AC":"24","PR":"2","TR":1240},
{"country":"AUSTRIA","month":"JAN","SR":"Brad P","AC":"64","PR":"12","TR":1700},
{"country":"ITALY","month":"JAN","SR":"Gim P","AC":"21","PR":"5","TR":900},
{"country":"UK","month":"FEB","SR":"John P","AC":"14","PR":"4","TR":540},
{"country":"AUSTRIA","month":"FEB","SR":"Brad P","AC":"24","PR":"12","TR":1700},
{"country":"ITALY","month":"FEB","SR":"Gim P","AC":"22","PR":"3","TR":600},
{"country":"UK","month":"MAR","SR":"John P","AC":"56","PR":"2","TR":1440},
{"country":"AUSTRIA","month":"MAR","SR":"Brad P","AC":"24","PR":"12","TR":700},
{"country":"ITALY","month":"MAR","SR":"Gim P","AC":"51","PR":"5","TR":200}
];
var tmpArray = [];
var obj =[];
for(var k=0; k<actual.length; k++){
var position = tmpArray.indexOf(actual[k].month);
if(position == -1){
tmpArray.push(actual[k].month);
val = {};
for(var i=0; i<actual.length; i++){
if(actual[i].month == actual[k].month){
val[actual[i].country] = actual[i]["AC"];
}
}
obj.push({month: actual[k].month, val:val});
}
}

How to access elements of arrays within array (JavaScript)?

I'm trying to access elements from a JavaScript array:
[["1","John"],["2","Rajan"],["3","Hitesh"],["4","Vin"],["5","ritwik"],["6","sherry"]]
I want to access
1, 2, 3, 4, 5, 6 separately in a variable and John, Rajan, Hitesh, Vin, Ritwik, Sherry separately in a variable.
I tried converting it to a string and split(), but it doesn't work.
this is code i tried
var jArray = <?php echo json_encode($newarray); ?> ;
var nJarr = jArray[0]; nJarr.toString();
var res = nJarr.split(","); var apname = res[0];
alert(apname);
but there's no alert appearing on the screen
If you are open to using Underscore, then it's just
var transposed = _.zip.apply(0, arr);
and the arrays you are looking for will be in transposed[0] and transposed[1].
You can write your own transpose function fairly easily, and it's more compact if you can use ES6 syntax:
transpose = arr => Object.keys(arr[0]).map(i => arr.map(e => e[i]));
>> transpose([["1","John"], ["2","Rajan"], ...]]
<< [[1, 2, ...], ["John", "Rajan", ...]]
If you want an ES5 version, here's one with comments:
function transpose(arr) { // to transpose an array of arrays
return Object.keys(arr[0]) . // get the keys of first sub-array
map(function(i) { // and for each of these keys
arr . // go through the array
map(function(e) { // and from each sub-array
return e[i]; // grab the element with that key
})
))
;
}
If you prefer old-style JS:
function transpose(arr) {
// create and initialize result
var result = [];
for (var i = 0; i < arr[0].length; i++ ) { result[i] = []; }
// loop over subarrays
for (i = 0; i < arr.length; i++) {
var subarray = arr[i];
// loop over elements of subarray and put in result
for (var j = 0; j < subarray.length; j++) {
result[j].push(subarray[j]);
}
}
return result;
}
Do it like bellow
var arr = [["1","John"],["2","Rajan"],["3","Hitesh"],["4","Vin"],["5","ritwik"],["6","sherry"]];
var numbers = arr.map(function(a){return a[0]}); //numbers contain 1,2,3,4,5
var names = arr.map(function(a){return a[1]}); //names contain John,Rajan...
Try this:
var data = [["1","John"],["2","Rajan"],["3","Hitesh"],["4","Vin"],["5","ritwik"],["6","sherry"]];
var IDs = [];
var names = [];
for(i=0; i<data.length; i++)
{
IDs.push(data[i][0]);
names.push(data[i][1]);
}
console.log(IDs);
console.log(names);
Here is the working fiddle.

How to extract values from an array of arrays in Javascript?

I have a variable as follows:
var dataset = {
"towns": [
["Aladağ", "Adana", [35.4,37.5], [0]],
["Ceyhan", "Adana", [35.8,37], [0]],
["Feke", "Adana", [35.9,37.8], [0]]
]
};
The variable has a lot of town data in it. How can I extract the first elements of the third ones from the data efficiently? I,e, what will ... be below?
var myArray = ...
//myArray == [35.4,35.8,35.9] for the given data
And what to do if I want to store both values in the array? That is
var myArray = ...
//myArray == [[35.4,37.5], [35.8,37], [35.9,37.8]] for the given data
I'm very new to Javascript. I hope there's a way without using for loops.
On newer browsers, you can use map, or forEach which would avoid using a for loop.
var myArray = dataset.towns.map(function(town){
return town[2];
});
// myArray == [[35.4,37.5], [35.8,37], [35.9,37.8]]
But for loops are more compatible.
var myArray = [];
for(var i = 0, len = dataset.towns.length; i < len; i++){
myArray.push(dataset.towns[i][2];
}
Impossible without loops:
var myArray = [];
for (var i = 0; i < dataset.towns.length; i++) {
myArray.push(dataset.towns[i][2][0]);
}
// at this stage myArray = [35.4, 35.8, 35.9]
And what to do if I want to store both values in the array?
Similar, you just add the entire array, not only the first element:
var myArray = [];
for (var i = 0; i < dataset.towns.length; i++) {
myArray.push(dataset.towns[i][2]);
}
// at this stage myArray = [[35.4,37.5], [35.8,37], [35.9,37.8]]

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