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How do I search a string in JavaScript array using jQuery? [duplicate]

This question already has answers here:
How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed 6 years ago.
I have a JavaScript array:
var j_array = new Array();
j_arry=["class:1","division:a","class:5","class:3","division:b","division:c","division:d","class:10"];
I need to find how many times the class is coming and its array key, so I use:
found = $.inArray('class', j_array); ` But it returns `-1`;
Then I use:
var search = 'class';
$.each([j_array], function(index, value){
$.each(value, function(key, cell){
if (search.indexOf(cell) !== -1)
console.log('found in array '+index, cell);
});
});
But that is also wrong. How do I solve this?
From this array I want to get the following:
Class coming 4 times, at key 0, 2, 3, and 7
I want to make a separate array of class only, that is,
new_array = ["class:1", "class:2", "class:3", "class:10"];
Currently there are four classes in j_array. How can I get the Nth class value
That is, 1st class value ="class:1", 2nd class value="class:5", etc.

You could filter elements which match in a new array and just return the length of this new array
var j_arry = ["class:1","division:a","class:5","class:3","division:b","division:c","division:d","class:10"];
var res = j_arry.filter(x => x.includes("class"));
var key = res.map(x => x.split(":")[1]);
console.log("Class coming " + res.length + " , at key " + key.join(","));
console.log("new array = ", res);

Use Array.prototype.filter to filter out the elements of the array that contains the string class - see demo below:
var j_array =["class:1","division:a","class:5","class:3","division:b","division:c","division:d","class:10"];
var result = j_array.filter(function(e){
return e.indexOf('class')!==-1;
});
console.log(result);
EDIT:
To get the list of indexes too, you can try this:
var j_array =["class:1","division:a","class:5","class:3","division:b","division:c","division:d","class:10"];
var filteredIndices = []
var filtered = j_array.filter(function(e,i){
if(e.indexOf('class')!==-1) {
filteredIndices.push(i);
return true;
} else {
return false;
}
});
console.log(filtered);
console.log(filteredIndices);
// Nth class value
console.log(filtered[2]); // this prints the 3rd one
.as-console-wrapper{top:0;max-height:100%!important;}

Here is the answer to your questions 1 + 2. It is also 'n' proof so answers your part 3 also. This works by old-fashioned hard graft rather than funky functions. The original array entries are split and filtered then if qualifying we store in an associative array (results) using a pointer array (list) to make it easier to give a sorted result and pull the values from the associative array. The max variable is probably not necessary but included for clarity - could have used list.length instead. Note that the list[] array will be sparse (missing steps) so we test each entry before use in the output steps.
var j_array = new Array();
j_arry=["class:1","division:a","class:5","class:3","division:b","division:c","division:d","class:10","class:1"];
var a, result = [], list=[], max = -1
for (var i =0; i < j_arry.length; i = i + 1) {
var a = j_arry[i].split(":")
if ( a[0] === "class") {
var key = "c" + a[1]
if ( !result[key] ) { result[key] = {pos:[]}}
result[key].cnt = result[key].cnt ? result[key].cnt + 1 : 1;
result[key].pos.push(i)
list[parseInt(a[1])] = "c" + a[1]
max = parseInt(a[1]) > max ? a[1] : max;
}
}
// say locations
for (var i = 0; i < max; i = i + 1) {
if (list[i]) {
key = "c" + i
console.log("Class " + i + " occurs at " + result[key].pos.toString() )
}
}
// make new array
var newArray=[]
for (var i = 0; i < max; i = i + 1) {
if (list[i]) {
newArray.push("Class:" + i)
}
}
console.log("New array=" + newArray.toString() )
Results are:
Class 1 occurs at 0,8
Class 3 occurs at 3
Class 5 occurs at 2
New array=Class:1,Class:3,Class:5

Single reduce is sufficient here.
var arr = ["class:1","division:a","class:5","class:3","division:b","division:c","division:d","class:10"],
res = arr.reduce((p,c) => c.includes("class") ? (p.count++, p.keys.push(c.split(":")[1]), p)
: p ,{count:0, keys:[]});
console.log(res);

You can use the filter and map functions to filter your array to have only elements that match the text 'class', and use array index notation to access the nth element in the array. Check the below code snippet I hope it will be of help to you.
The below code snippet uses ES6 arrow syntax.
var arr = ["class:1", "division:a", "class:5", "class:3", "division:b", "division:c", "division:d", "class:10"];
var result = arr.filter(x => x.indexOf('class') !== -1);
var indices = result.map(x => arr.indexOf(x));
console.log(indices);
console.log(result);
var nValue = window.prompt('Enter n value');
console.log(result[nValue]);

If you're using jQuery to support some really old browser that still don't implement the new Array functions, and you don't want to polyfill those because you're already using jQuery, then you can use the jQuery equivalents:
var arr = ["class:1", "division:a", "class:5", "class:3", "division:b", "division:c", "division:d", "class:10"]
var result = $.grep(arr, function (x) { return x.indexOf('class') !== -1 })
var indices = $.map(result, function (x) { return arr.indexOf(x) })
This is the same code as this answer, but using jQuery.

You have to do map first then filter.
var j_array = ["class:1", "division:a", "class:5", "class:3", "division:b", "division:c", "division:d", "class:10"];
var result = j_array.map(function(e, i) {
return e.indexOf('class') > -1 ? '' + i : false;
}).filter(function(e) {
return !!e;
});
console.log(result);

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]

Associative array was sorting indexs if it return from regexp

I need to save order in array. A normal array was destroying it, so i found associative array, but with indexes from regexp was sorting records too.
My function is
var myArray = {};
var searchIndex = '';
$("#searchList").find('li').each(function( index ) {
id = $( this ).attr('id');
if(id.match(/search(:?\d+|\w+)/)){
searchIndex = id.match(/search(\d+|\w+)/)[1];
myArray[searchIndex] = "empty";
}
});
This code works well, order are saved.
myArray[id] = "empty";
http://screenshooter.net/100008827/fhbsvjm
But when i want to remove string "search" from id, by regexp, array just sorting indexes...
searchIndex = id.match(/search(\d+|\w+)/)[1];
myArray[searchIndex] = "empty";
http://screenshooter.net/100008827/gmxusyu
But order should be last->7->9->8

JavaScript does not have associative arrays. The plain objects in JavaScript are similar to associative arrays in some ways, but the order of their properties is not guaranteed.
If you want an associative array that preserves the order of items in the order they were added, it is possible to create one from scratch. Here is a fairly simple implementation that provides that functionality:
function AssociativeArray() {
var items = [];
var refs = {};
this.set = function(key, value) {
if (key in refs) {
refs[key].value = value;
} else {
var entry = { key: key, value: value };
items.push(entry);
refs[key] = entry;
}
};
this.get = function(key) {
var entry = refs[key];
return entry && entry.value;
};
this.allItems = function() {
return items.slice();
};
}
var assoc = new AssociativeArray();
assoc.set(7, "hello");
assoc.set(3, "goodbye");
assoc.set("cheer", "yay");
var items = assoc.allItems();
for (var i = 0; i < items.length; i += 1) {
console.log(items[i].key + " - " + items[i].value);
}
console.log("The item with key 7 is: " + assoc.get(7));
The way you would adapt this to your current code is:
var myArray = new AssociativeArray();
$("#searchList").find('li').each(function( index ) {
var id = $( this ).attr('id'),
searchIndex;
if(id.match(/search(:?\d+|\w+)/)){
searchIndex = id.match(/search(\d+|\w+)/)[1];
myArray.set(searchIndex, "empty");
}
});
The first code snippet above shows how to iterate through the array in the order that items were added.

How to convert arrays into an array of objects

Hi I'm trying to make an array of objects from several arrays.This is probably a very basic question, but I didn't find a proper way of doing it from searching online. :(
The original data I've got is
valueYes = [15,30,22,18,2,6,38,18];
valueNo = [23,75,45,12,45,9,17,23];
valueNotSure = [1,-1,1,1,-1,-1,-1,1];
What I want to achieve is an array like :
data = [object1, object2,.....]
Each object is made of :
object1 = {valueYes:15, valueNo:23,valueNotSure:1}
object2 = {valueYes:30, valueNo:75,valueNotSure:-1}
.......
my current code is a bit messy, which only return me an empty value of each key:
valueYes = [15,30,22,18,2,6,38,18];
valueNo = [23,75,45,12,45,9,17,23];
valueNotSure = [1,-1,1,1,-1,-1,-1,1];
var object1 = Object.create({}, {
myChoice: { value: function(myChoice) {for (var i = 0; i < len; i++){return this.myChoice[i] = myChoice[i];} } }
});

Assuming all your arrays have the same size:
valueYes = [15,30,22,18,2,6,38,18];
valueNo = [23,75,45,12,45,9,17,23];
valueNotSure = [1,-1,1,1,-1,-1,-1,1];
var data = [];
for(var i = 0; i < valueYes.length; i++){
data.push({
valueYes: valueYes[i],
valueNo: valueNo[i],
valueNotSure: valueNotSure[i]
});
}

You could use something like below;
var objs = valueYes.map(function (v, i) {
return {
valueYes: v,
valueNo: valueNo[i],
valueNotSure: valueNotSure[i]
};
});
... this uses the map() Array method, and assumes that all the arrays are the same length...

This?
var valueYes = [15,30,22,18,2,6,38,18];
var valueNo = [23,75,45,12,45,9,17,23];
var valueNotSure = [1,-1,1,1,-1,-1,-1,1];
var data = [];
valueYes.forEach(function(item, index) {
data.push({ valueYes: valueYes[index], valueNo: valueNo[index], valueNotSure: valueNotSure[index] });
});
console.log(data);
http://jsfiddle.net/chrisbenseler/9t1y1zhk/

Combining results into one object

I'm looping through a set of inputs. I need to tally up the grouped totals. The inputs below to one of three categories.
How do I go about combining the values up relevant to three categories?
var compoundedArray = new Array();
holder.find(".dataset input").each(function(index) {
var val = $(this).val();
var dataType = $(this).data("type");
var localObj = {};
localObj[dataType] = val;
compoundedArray.push(localObj);
});
I have an object like this
[
{
"growth":30
},
{
"growth": 40
},
{
"other": 20
}
]
how do I loop through the object to produce something like
[
{
"growth": 70
},
{
"other": 20
}
]
if I looped over the initial array object
for (var i = 0; i < compoundedArray.length; i++) {
console.log(compoundedArray[i]);
}
how would I go about checking to ensure I don't have duplicates - and that I can tally up the results?
Ideally the resulting format may be the best
var array = [
"matching": 50,
"growth": 20
]

var array = [
"matching": 50,
"growth": 20
]
is not valid JS, but you can create an object of the form
var obj = {
"matching": 50,
"growth": 20
};
And that's pretty easy to do, just use an object from the very beginning:
var result = {};
holder.find(".dataset input").each(function(index) {
var val = +$(this).val(); // use unary plus to convert to number
var dataType = $(this).data("type");
result[dataType] = (result[dataType] || 0) + val;
});
Further reading material:
MDN - Working with Objects
Eloquent JavaScript - Data structures: Objects and Arrays

You can just use an object (not array) with unique keys.
var compoundedObj = {};
$(".dataset input", holder).each(function() {
var dataType = $(this).data("type");
if(!compoundedObj.hasOwnProperty(dataType)) {
compoundedObj[dataType] = 0;
}
compoundedObj[dataType] += parseInt($(this).val(), 10);
});
In this way you'll get an object like this:
{
"growth": 70,
"other": 20
}
Live demo

http://jsfiddle.net/GFwGU/
var original = [{"growth":30},{"growth": 40},{"other": 20}]
// object to sum all parts by key
var sums = {}
// loop through original object
for(var index in original){
// get reference to array value (target object)
var outer = original[index]
// loop through keys of target object
for(var key in outer){
// get a reference to the value
var value = outer[key]
// set or add to the value on the sums object
sums[key] = sums[key] ? sums[key] + value : value
}
}
// create the output array
var updated = []
// loop through all the summed keys
for(var key in sums){
// get reference to value
var value = sums[key]
// create empty object
var dummy = {}
// build object into desired format
dummy[key] = value
// push to output array
updated.push(dummy)
}
// check the results
alert(JSON.stringify( updated ))

var add=function (a,b){ a=a||0; b=b||0; return a+b};
var input=[ {growth:30},{growth:40},{other:20} ],output=[],temp={};
$.each(input,function(i,o){
var n;
for(i in o)
{n=i;break}
temp[n]=add(temp[n],o[n]);
});
$.each(temp,function(i,o){
var k={};
k[i]=o;
output.push(k)
});