Javascript transform array into grouped object by value - javascript

I have an array:
["car1-coupe", "car2-convertible", "car2-hatchback", "car2-estate", "car3-hatchback", "car3-estate"]
The array can have different sets of cars, and I want to turn it into something like this:
[{
car1: ["car1-coupe"]
},{
car2: ["car2-convertible", "car2-hatchback", "car2-estate"]
},{
car3: ["car3-hatchback", "car3-estate"]
}]
How can I do this in JavaScript or Underscore?

So, assuming an array like this:
var a = ["car1-coupe", "car2-convertible", "car2-hatchback", "car2-estate", "car3-hatchback", "car3-estate"];
You can do this:
var b = a.reduce(function(prev, curr){
var car = curr.split('-')[0]; // "get" the current car
prev[car] = prev[car] || []; // Initialize the array for the current car, if necessary.
prev[car].push(curr); // Add the current item to the array.
return prev;
}, {});
This will return the following object:
{
car1: ["car1-coupe"],
car2: ["car2-convertible", "car2-hatchback", "car2-estate"],
car3: ["car3-hatchback", "car3-estate"]
}

var array = ["car1-coupe", "car2-convertible", "car2-hatchback", "car2-estate", "car3-hatchback", "car3-estate"];
var result = {};
for (var i = 0; i < array.length; i++) {
var key = array[i].split('-')[0]; // The car we're interested in
if (result[key]) { // Check if this car has already been initialized
result[key].push(array[i]); //add this model to the list
} else {
result[key] = [array[i]]; // initialize the array with the first value
}
}
console.log(result);
/*will return :
{
car1: ["car1-coupe"],
car2: ["car2-convertible", "car2-hatchback", "car2-estate"],
car3: ["car3-hatchback", "car3-estate"]
}
*/

var myObj = {}, myArr = [];
for( var i = 0; i < arr.length; i+=1) {
var key = arr[i].split("-")[0];
myObj = {};
myObj[key] = [];
for( var j = i; j < arr.length; j+=1 ) {
if( key === arr[j].split("-")[0])
myObj[key].push(arr[j]);
}
myArr.push(myObj);
}
I think this can be done simply with this way. One loop to get the key and another inner loop to get all values of this key.

Related

Sum of same object name in javascript

Hi friends I'm beginner for javascript how i sum same n no's of object name corresponding value and push the result to new array.see this is sample object
var obj_1 ={'delivered':10,'due':11,'team_name':'UK'};
var obj_2 ={'delivered':10,'due':11,'team_name':'US'};
var obj_nth ={'delivered':10,'due':11,'team_name':'UK'};
but i expect this output [UK:{'delivered':20,'due':22},US:{'delivered':10,'due':11}],so please help me what i'll do next
You can first create array of objects and then reduce() to return one object.
var obj_1 ={'delivered':10,'due':11,'team_name':'UK'};
var obj_2 ={'delivered':10,'due':11,'team_name':'US'};
var obj_nth ={'delivered':10,'due':11,'team_name':'UK'};
var result = [obj_1, obj_2, obj_nth].reduce(function(r, e) {
if(!r[e.team_name]) {
r[e.team_name] = {delivered:0,due:0}
}
r[e.team_name].delivered += e.delivered
r[e.team_name].due += e.due
return r
}, {})
console.log(result)
const newArray = initialArray.map(({team_name, ...restProps}) => {
return {
[team_name]: {...restProps}
};
});
See:
Arrow functions
Spread operator
Array.prototype.map
Computed property names
var obj_1 ={'delivered':10,'due':11,'team_name':'UK'};
var obj_2 ={'delivered':10,'due':11,'team_name':'US'};
var obj_nth ={'delivered':10,'due':11,'team_name':'UK'};
function sum_all() {
var sum={};
for(var i=0;i<arguments.length;i++) {
obj = arguments[i];
if (!sum[obj.team_name]) {
sum[obj.team_name]={'delivered':0,'due':0};
}
sum[obj.team_name].delivered += obj.delivered;
sum[obj.team_name].due += obj.due;
}
return sum;
}
var sum = sum_all(obj_1,obj_2,obj_nth);
console.log(sum);
Your console output will be:
sum
Object
UK: Object
delivered: 20
due: 22
US: Object
delivered: 10
due: 11
Store these objects in an array, such as:
var myObjects = [
{'delivered':10,'due':11,'team_name':'UK'},
{'delivered':10,'due':11,'team_name':'US'},
{'delivered':10,'due':11,'team_name':'UK'}
];
Create a new object in which you will store your results:
var results = {};
Then iterate through the array with a for loop (as it is generally faster) and add the other properties according to team_name:
for (var i = 0; i <= myObjects.length; i++) {
if (typeof results[myObjects[i].team_name] !== undefined) {
results[myObjects[i]].delivered += myObjects[i].delivered;
results[myObjects[i]].due += myObjects[i].due;
} else {
// Set 0 to these properties if the entry didn't exist
results[myObjects[i]].delivered = 0;
results[myObjects[i]].due = 0;
}
}

push only unique elements in an array

I have array object(x) that stores json (key,value) objects. I need to make sure that x only takes json object with unique key. Below, example 'id' is the key, so i don't want to store other json objects with 'item1' key.
x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}]
var clickId = // could be "item1", "item2"....
var found = $.inArray(clickId, x); //
if(found >=0)
{
x.splice(found,1);
}
else{
x.push(new Item(clickId, obj)); //push json object
}
would this accomplish what you're looking for? https://jsfiddle.net/gukv9arj/3/
x = [
{"id":"item1","val":"Items"},
{"id":"item1","val":"Items"},
{"id":"item2","val":"Items"}
];
var clickId = [];
var list = JSON.parse(x);
$.each(list, function(index, value){
if(clickId.indexOf(value.id) === -1){
clickId.push(value.id);
}
});
You can't use inArray() because you are searching for an object.
I'd recommend rewriting a custom find using Array.some() as follows.
var x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}]
var clickId = "item1";
var found = x.some(function(value) {
return value.id === clickId;
});
alert(found);
Almost 6 years later i ended up in this question, but i needed to fill a bit more complex array, with objects. So i needed to add something like this.
var values = [
{value: "value1", selected: false},
{value: "value2", selected: false}
//there cannot be another object with value = "value1" within the collection.
]
So I was looking for the value data not to be repeated (in an object's array), rather than just the value in a string's array, as required in this question. This is not the first time i think in doing something like this in some JS code.
So i did the following:
let valueIndex = {};
let values = []
//I had the source data in some other and more complex array.
for (const index in assetsArray)
{
const element = assetsArray[index];
if (!valueIndex[element.value])
{
valueIndex[element.value] = true;
values.push({
value: element.value,
selected: false
});
}
}
I just use another object as an index, so the properties in an object will never be repated. This code is quite easy to read and surely is compatible with any browser. Maybe someone comes with something better. You are welcome to share!
Hopes this helps someone else.
JS objects are great tools to use for tracking unique items. If you start with an empty object, you can incrementally add keys/values. If the object already has a key for a given item, you can set it to some known value that is use used to indicate a non-unique item.
You could then loop over the object and push the unique items to an array.
var itemsObj = {};
var itemsList = [];
x = [{"id":"item1","val":"foo"},
{"id":"item2","val":"bar"},
{"id":"item1","val":"baz"},
{"id":"item1","val":"bez"}];
for (var i = 0; i < x.length; i++) {
var item = x[i];
if (itemsObj[item.id]) {
itemsObj[item.id] = "dupe";
}
else {
itemsObj[item.id] = item;
}
}
for (var myKey in itemsObj) {
if (itemsObj[myKey] !== "dupe") {
itemsList.push(itemsObj[myKey]);
}
}
console.log(itemsList);
See a working example here: https://jsbin.com/qucuso
If you want a list of items that contain only the first instance of an id, you can do this:
var itemsObj = {};
var itemsList = [];
x = [{"id":"item1","val":"foo"},
{"id":"item2","val":"bar"},
{"id":"item1","val":"baz"},
{"id":"item1","val":"bez"}];
for (var i = 0; i < x.length; i++) {
var item = x[i];
if (!itemsObj[item.id]) {
itemsObj[item.id] = item;
itemsList.push(item);
}
}
console.log(itemsList);
This is late but I did something like the following:
let MyArray = [];
MyArray._PushAndRejectDuplicate = function(el) {
if (this.indexOf(el) == -1) this.push(el)
else return;
}
MyArray._PushAndRejectDuplicate(1); // [1]
MyArray._PushAndRejectDuplicate(2); // [1,2]
MyArray._PushAndRejectDuplicate(1); // [1,2]
This is how I would do it in pure javascript.
var x = [{"id":"item1","val":"Items"},{"id":"item1","val":"Items"},{"id":"item1","val":"Items"}];
function unique(arr, comparator) {
var uniqueArr = [];
for (var i in arr) {
var found = false;
for (var j in uniqueArr) {
if (comparator instanceof Function) {
if (comparator.call(null, arr[i], uniqueArr[j])) {
found = true;
break;
}
} else {
if (arr[i] == uniqueArr[j]) {
found = true;
break;
}
}
}
if (!found) {
uniqueArr.push(arr[i]);
}
}
return uniqueArr;
};
u = unique(x, function(a,b){ return a.id == b.id; });
console.log(u);
y = [ 1,1,2,3,4,5,5,6,1];
console.log(unique(y));
Create a very readable solution with lodash.
x = _.unionBy(x, [new Item(clickId, obj)], 'id');
let x = [{id:item1,data:value},{id:item2,data:value},{id:item3,data:value}]
let newEle = {id:newItem,data:value}
let prev = x.filter(ele=>{if(ele.id!=new.id)return ele);
newArr = [...prev,newEle]

merge two json arrays with push on item value

I have the following json array:
array 1:
fruits1 = [{"fruit":"banana","amount":"2","color":"yellow"},{"fruit":"apple","amount":"5","color":"red"},{"fruit":"kiwi","amount":"1","color":"green"}]
array 2:
fruits2 = [{"fruit":"banana","sold":"1","stock":"3"},{"fruit":"apple","sold":"3","stock":"5"},{"fruit":"kiwi","sold":"2","stock":"3"}]
I would like to get just one array which has the results merged according to the fruits value like this:
fruits = [{"fruit":"banana","amount":"2","color":"yellow","sold":"1","stock":"3"},{"fruit":"apple","amount":"5","color":"red","sold":"3","stock":"5"},{"fruit":"kiwi","amount":"1","color":"green","sold":"2","stock":"3"}]
I need to do something like
foreach item.fruit where fruit = fruit from initial array
fruits.push item
Any idea?
Try this logic:
function merge_options(obj1,obj2){
var obj3 = {};
for (var attrname in obj1) { obj3[attrname] = obj1[attrname]; }
for (var attrname in obj2) { obj3[attrname] = obj2[attrname]; }
return obj3;
}
var obj1 = [];
for (var i = 0; i < fruits1.length ; i++) {
obj1[fruits1[i].fruit] = fruits1[i];
}
var obj2 = [];
for (var i = 0; i < fruits2.length ; i++) {
obj2[fruits2[i].fruit] = fruits2[i];
}
var fruits = []
for (var key in obj1) {
fruits.push(merge_options(obj1[key],obj2[key]));
}
console.log(fruits);
You can do something like this with javascript
// create a hash like {fruit_name -> object}
f1 = {};
fruits1.forEach(function(p) {
f1[p.fruit] = p;
});
// merge second array into above hash on fruit_name
fruits2.forEach(function(p) {
for (var a in p) { f1[p.fruit][a] = p[a];}
});
//fruits1 will now contain result;
//if you don't want to spoil fruit1 array, clone p inside 'fruits1.forEach' above before assigning it to 'f1[p.fruit]'. And at the end, create a new array out of f1
Here's a generic way that works with your data:
function joinObjects(initial, other, predicate, valueSelector) {
if(typeof(predicate) !== 'function') throw 'predicate must be a function';
if(typeof(valueSelector) !== 'function') throw 'valueSelector must be a function';
// make a clone of the original object so its not modified
var clone = jQuery.extend(true, {}, initial);
// iterate over the initial and other collections
for(var cloneKey in clone) {
if (!clone.hasOwnProperty(cloneKey)) continue;
for(var otherKey in other) {
if (!other.hasOwnProperty(otherKey)) continue;
// if the predicate is truthy, get the values
if (predicate(clone[cloneKey], other[otherKey])) {
// pull only the values you want to merge
var values = valueSelector(other[otherKey]);
// iterate over the values add them to the cloned initial object
for(var valueKey in values) {
if (values.hasOwnProperty(valueKey)) {
clone[cloneKey][valueKey] = values[valueKey];
}
}
}
}
}
return clone;
}
var fruits1 = [{"fruit":"banana","amount":"2","color":"yellow"},{"fruit":"apple","amount":"5","color":"red"},{"fruit":"kiwi","amount":"1","color":"green"}];
var fruits2 = [{"fruit":"banana","sold":"1","stock":"3"},{"fruit":"apple","sold":"3","stock":"5"},{"fruit":"kiwi","sold":"2","stock":"3"}];
var finalFruits = joinObjects(fruits1, fruits2,
function(left, right) { return left.fruit == right.fruit },
function(other) {
return {
sold: other.sold,
stock: other.stock
};
});
console.log(finalFruits);

Converting js array into dictionary map

I have this array:
["userconfig", "general", "name"]
and I would like it to look like this
data_structure["userconfig"]["general"]["name"]
I have tried this function:
inputID = "userconfig-general-name"
function GetDataByID(inputID){
var position = '';
for (var i = 0; i < inputID.length; i++) {
var hirarchy = inputID[i].split('-');
for (var index = 0; index < hirarchy.length; index++) {
position += '["'+ hirarchy[index] +'"]';
}
}
return data_structure[position];
}
while hirarchy is the array. I get the [position] as a string which is not working well.
how can I make a js function which builds the object path dynamically by an array?
var arr = ["userconfig", "general", "name"];
var dataStructure = arr.reduceRight(function (value, key) {
var obj = {};
obj[key] = value;
return obj;
}, 'myVal');
Ends up as:
{ userconfig : { general : { name : 'myVal' } } }
Note that you may need a polyfill for the reduceRight method: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/ReduceRight
The below function will take an object to modify and an array filled with the properties needed:
function objPath(obj,path){
path.forEach(function(item){
obj[item] = {};
obj = obj[item];
});
}
var myobj = {};
objPath(myobj,["test","test2","test3"]);
console.log(myobj);
//outputs
Object {test: Object}
test: Object
test2: Object
test3: Object
The function loops over the array creating the new object property as a new object. It then puts a reference to the new object into obj so that the next property on the new object can be made.
JSFiddle
Recursive function
var array = ["userconfig", "general", "name"];
function toAssociative(array) {
var index = array.shift();
var next = null;
if (array.length > 0) {
next = toAssociative(array);
}
var result = new Array();
result[index] = next;
return result;
}

Find index in array of objects

I would like to find index in array. Positions in array are objects, and I want to filter on their properties. I know which keys I want to filter and their values. Problem is to get index of array which meets the criteria.
For now I made code to filter data and gives me back object data, but not index of array.
var data = [
{
"text":"one","siteid":"1","chid":"default","userid":"8","time":1374156747
},
{
"text":"two","siteid":"1","chid":"default","userid":"7","time":1374156735
}
];
var filterparams = {userid:'7', chid: 'default'};
function getIndexOfArray(thelist, props){
var pnames = _.keys(props)
return _.find(thelist, function(obj){
return _.all(pnames, function(pname){return obj[pname] == props[pname]})
})};
var check = getIndexOfArray(data, filterparams ); // Want to get '2', not key => val
Using Lo-Dash in place of underscore you can do it pretty easily with _.findIndex().
var index = _.findIndex(array, { userid: '7', chid: 'default' })
here is thefiddle hope it helps you
for(var intIndex=0;intIndex < data.length; intIndex++){
eachobj = data[intIndex];
var flag = true;
for (var k in filterparams) {
if (eachobj.hasOwnProperty(k)) {
if(eachobj[k].toString() != filterparams[k].toString()){
flag = false;
}
}
}
if(flag){
alert(intIndex);
}
}
I'm not sure, but I think that this is what you need:
var data = [{
"text":"one","siteid":"1","chid":"default","userid":"8","time":1374156747
}, {
"text":"two","siteid":"1","chid":"default","userid":"7","time":1374156735
}];
var filterparams = {userid:'7', chid: 'default'};
var index = data.indexOf( _.findWhere( data, filterparams ) );
I don't think you need underscore for that just regular ole js - hope this is what you are looking for
var data = [
{
"text":"one","siteid":"1","chid":"default","userid":"8","time":1374156747
},
{
"text":"two","siteid":"1","chid":"default","userid":"7","time":1374156735
}
];
var userid = "userid"
var filterparams = {userid:'7', chid: 'default'};
var index;
for (i=0; i < data.length; i++) {
for (prop in data[i]) {
if ((prop === userid) && (data[i]['userid'] === filterparams.userid)) {
index = i
}
}
}
alert(index);

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