Related
$.each(constructions, function(i,v) {
if ($.inArray(v.name, map[ii].buildings) == -1) {//stuff}
};
Where constructions is an array of objects, each with a unique name. map[ii].buildings is an array containing some of these objects. I want to iterate each object in constructions, checking if its name parameter appears in the objects of map[ii].buildings.
The above code works if the each element in the map[ii].buildings array is just the text string of the object name, but not if the element is the entire object.. close, but no dice >.<
Try using $.grep() instead of $.inArray(); you can specify a function to do the filtering for you.
Instead of checking for -1, you check whether the array that $.grep() returns has length == 0
Simple example: (would be easier if you posted the code / example of what "constructions" objects look like)
var constructions = [{
Name: "Mess hall",
SqFt: 5000
}, {
Name: "Infirmary",
SqFt: 2000
}, {
Name: "Bungalow",
SqFt: 2000
}, {
Name: "HQ",
SqFt: 2000
}];
var buildings = [{
Name: "Infirmary",
SqFt: 2000
}, {
Name: "HQ",
SqFt: 2000
}];
// found buildings will be list of items in "constructions" that is not in "buildings"
var foundBuildings = $.grep(constructions, function (constructionsItem) {
return $.grep(buildings, function (buildingsItem) {
return buildingsItem.Name === constructionsItem.Name
}).length == 0; // == 0 means "not in", and > 0 means "in"
});
// this just renders the results all pretty for ya
$.each(foundBuildings, function (idx, item) {
$("#output").append("<div>" + item.Name + "</div>");
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id='output'></div>
Example jsFiddle: http://jsfiddle.net/eLeuy9eg/3/
The non-jQuery way of doing this would be to use filter. Something like this:
// pass in an array and the key for which you want values
// it returns an array of those values
function getValues(arr, key) {
return arr.map(function (el) { return el[key]; });
}
function notFoundIn(arr, arr2) {
// grab the names of the buildings
var buildings = getValues(arr2, 'name');
// grab the names from the construction objects and filter
// those that are not in the building array
return getValues(arr, 'name').filter(function (el) {
return buildings.indexOf(el) === -1;
});
}
notFoundIn(constructions, buildings); // eg [ "one", "three" ]
DEMO
You could even add a new method to the array prototype. With this one you can use either simple arrays, or arrays of objects if you pass in a key. Note in this example I've replaced map and filter with loops that perform the same functions, but faster (see comments):
function getValues(arr, key) {
var out = [];
for (var i = 0, l = arr.length; i < l; i++) {
out.push(arr[i][key]);
}
return out;
}
if (!Array.prototype.notFoundIn) {
Array.prototype.notFoundIn = function (inThisArray, key) {
var thisArr = key ? getValues(this, key) : this;
var arrIn = key ? getValues(inThisArray, key) : inThisArray;
var out = [];
for (var i = 0, l = thisArr.length; i < l; i++) {
if (arrIn.indexOf(thisArr[i]) === -1) {
out.push(thisArr[i]);
}
}
return out;
}
}
constructions.notFoundIn(buildings, 'name');
[1, 2, 3].notFoundIn([2]); // [1, 3]
DEMO
Given data such as :
var people = [
{ 'myKey': 'John Kenedy', 'status': 1 },
{ 'myKey': 'Steeven Red', 'status': 0 },
{ 'myKey': 'Mary_Kenedy', 'status': 3 },
{ 'myKey': 'Carl Orange', 'status': 0 },
{ 'myKey': 'Lady Purple', 'status': 0 },
... // thousands more
];
How to efficiently get the list of all objects which contains in myKey the string Kenedy ?
http://jsfiddle.net/yb3rdhm8/
Note: I currently use str.search() :
The search("str") returns the position of the match. Returns -1 if no match is found.
to do as follow :
var map_partial_matches = function(object, str){
var list_of_people_with_kenedy = [] ;
for (var j in object) {
if (object[j]["myKey"].search(str) != -1) {
object[j].presidentName = "yes"; // do something to object[j]
list_of_people_with_kenedy.push({ "people": object[j]["myKey"] }); // add object key to new list
}
} return list_of_people_with_kenedy;
}
map_partial_matches(people, "Kenedy");
I could do the same using str.match() :
str.match() returns the matches, as an Array object. Returns null if no match is found.
It works anyway, but I have no idea if it's efficient or completely dump.
You can use filter():
var filtered = people.filter(function (item) {
if (item.myKey.indexOf("Kenedy") != -1)
return item;
});
You can also checkout Sugar.js
In order to search your unsorted object you need to get through all of it's properties - So I'd say a simple loop with an indexOf will be pretty much the best you can go:
var foundItems = [];
for(var i = 0; i < people.length ;i++)
{
if(people[i].myKey.indexOf('Kenedy') > -1)
foundItems.push(people[i]]);
}
Maybe you can tweak it up a little, but it's pretty much the best you can get.
You can write a basic function that uses filter to return an array of matches based on a key and value:
function find(arr, key, val) {
return arr.filter(function (el) {
return el[key].indexOf(val) > -1;
});
}
var result = find(people, 'myKey', 'Kenedy');
Alternatively use a normal for...loop:
function find(arr, key, val) {
var out = [];
for (var i = 0, l = arr.length; i < l; i++) {
if (arr[i][key].indexOf(val) > -1) {
out.push(arr[i]);
}
}
return out;
}
DEMO
Does the Object Contain a Given Key?
function hKey(obj, key) {
arr = [];
// newarr =[];
for(el in obj){
arr.push(el)
} //return arr;
for(i=0; i<arr.length; i++){
name = arr[i]
} if(name == key) {
return true;
}else {
return false;
}
}
console.log(hKey({ a: 44, b: 45, c: 46 }, "c"))
I have an array like this:
employees = [
{
"id": 1,
"shift_id": 1,
"days": {
"2012-03-01": 1,
"2012-03-02": 1,
"2012-03-03": 1,
"2012-03-04": 0,
"2012-03-05": 0,
"2012-03-06": 0
}},
{
"id": 2,
"shift_id": 1,
"days": {
"2012-03-01": 0,
"2012-03-02": 1,
"2012-03-03": 1,
"2012-03-04": 1,
"2012-03-05": 1,
"2012-03-06": 0
}},
{
"id": 3,
"shift_id": 2,
"days": {
"2012-03-01": 0,
"2012-03-02": 0,
"2012-03-03": 1,
"2012-03-04": 1,
"2012-03-05": 1,
"2012-03-06": 1
}}
];
is there a way to access an element in this array using the id value?
maybe something in jquery?
like $(employees('id = 1');
Just loop through your array and check for the id:
var yourId = 1;
for (var i = 0, len = employees.length; i < len; i++) {
if (employees[i].id == yourId) {
// ...
}
}
You can use a function like this, which filters the array appropriately:
var getEmployee = function (id) {
return employees.filter(function(i) { return i.id == id; });
};
You can use .grep() method documented here:
var employee = $.grep(employees, function(e) { return e.id == 1 })[0];
Well, there's a jQuery way of doing it:
var findElementById = function(elements, id) {
return $.grep(elements, function(e) { return e.id === id; })[0];
}
Still I wonder why don't you just index the source array by id instead.
Maybe you are looking for something like the below:
$.grep(employees, function(n){return n.id==1});
Or this:
$.each(employee, function(){
if(this["id"] == 2){
console.log(this);
}
});
As far as I am aware, in order to achieve that you would have to loop through them
Array.prototype.getObjectById = function(x){
var catcher = false, i = 0;
while(!catcher){
catcher = this[i].id == x ? this[i] : false;
i++;
}
return catcher;
}
This function should help. It will extend the array object so you can use it as myArray.getObjectbyId(id);
By design, this will return the first object that meets the criteria. You could extend it like so:
Array.prototype.getObjectsById = function(x){
var catcher = [], i = 0;
for(var i = 0; i < this.length; i++){
if(this[i].id == value){
catcher.push(this[i]);
}
i++;
}
return catcher.length == 1 ? catcher[0] : catcher;
}
This will return an array of objects if more than one object matches the criteria.
Array.prototype.getObjectsByAttribute = function(x, criteria){
if(!criteria){criteria = 'id';}
var catcher = [], i = 0;
for(var i = 0; i < this.length; i++){
if(this[i].criteria == value){
catcher.push(this[i]);
}
i++;
}
return catcher.length == 1 ? catcher[0] : catcher;
}
This extends it further to look for any criteria.
I know this question is old, but for future reference if anyone else stumbles upon this question ...
Instead of trying to over-engineer a function to parse/examine your JSON, consider changing the structure of your data to suit its purpose.
Consider the example in the question:
data = [ {
"id": 1,
"shift_id": 1,
"days": {
"2012-03-01": 1,
"2012-03-02": 1,
"2012-03-03": 1,
"2012-03-04": 0,
"2012-03-05": 0,
"2012-03-06": 0
}}, { .. }, {...} ]
Structuring the data in this way only gives you sequential access to the objects with no way to lookup an object by a particular index. Array indices are generally meaningless in this context.
data[0] => { id : 1, .. }
data[1] => { id : 2, .. }
What happens if the id is non-sequential or alphanumeric?
Using an array wont help you search any faster, you'll still have to loop...
Instead consider using a hash table/object:
{
'id1' => { id : 1 , data : { ... } },
'id99' => { id : 99, data : { ... } },
'id2' => { id : 2 , data : { ... } },
}
You can use a string value for the key and get direct access to the data by doing something like:
data['id2'] => { id : 2, ... }
Which will give you direct access to the data you want to find (by id). By simply re-organizing the structure of the data we were able to go from a O(n) search to an O(1) search.
Keep in mind that this method may work better for some solutions than others, and there are a number of other considerations to make.
This is just one approach to how you might solve a problem when you want to lookup data by a unique property.
The accepted answer is great - modified a bit for an AngularJS app:
$rootScope.getObjectsByAttribute = function(inarry,infldnm,infldval){
// This will iterate through a fetchAll sql result set and return rows where fldnm==fldval
// If it finds 1 row it returns a single object, if more than that it returns an array of objects
// Usage: result = $rootScope.getObjectsByAttribute(myarray,'myfldnm',myfldval);
if(!infldnm){infldnm = 'id';}
var catcher = [], i = 0;
for(i = 0; i < inarry.length; i++){
if(inarry[i][infldnm] == infldval){
catcher.push(inarry[i]);
}
}
return catcher.length == 1 ? catcher[0] : catcher;
}
For example, I have:
var Data = [
{ id_list: 1, name: 'Nick', token: '312312' },
{ id_list: 2, name: 'John', token: '123123' },
]
Then, I want to sort/reverse this object by name, for example. And then I want to get something like this:
var Data = [
{ id_list: 2, name: 'John', token: '123123' },
{ id_list: 1, name: 'Nick', token: '312312' },
]
And now I want to know the index of the object with property name='John' to get the value of the property token.
How do I solve the problem?
Since the sort part is already answered. I'm just going to propose another elegant way to get the indexOf of a property in your array
Your example is:
var Data = [
{id_list:1, name:'Nick', token:'312312'},
{id_list:2, name:'John', token:'123123'}
]
You can do:
var index = Data.map(function(e) { return e.name; }).indexOf('Nick');
var Data = [{
id_list: 1,
name: 'Nick',
token: '312312'
},
{
id_list: 2,
name: 'John',
token: '123123'
}
]
var index = Data.map(function(e) {
return e.name;
}).indexOf('Nick');
console.log(index)
Array.prototype.map is not available on Internet Explorer 7 or Internet Explorer 8. ES5 Compatibility
And here it is with ES6 and arrow syntax, which is even simpler:
const index = Data.map(e => e.name).indexOf('Nick');
If you're fine with using ES6, arrays now have the findIndex function. Which means you can do something like this:
const index = Data.findIndex(item => item.name === 'John');
As the other answers suggest, looping through the array is probably the best way. But I would put it in its own function, and make it a little more abstract:
function findWithAttr(array, attr, value) {
for(var i = 0; i < array.length; i += 1) {
if(array[i][attr] === value) {
return i;
}
}
return -1;
}
var Data = [
{id_list: 2, name: 'John', token: '123123'},
{id_list: 1, name: 'Nick', token: '312312'}
];
With this, not only can you find which one contains 'John', but you can find which contains the token '312312':
findWithAttr(Data, 'name', 'John'); // returns 0
findWithAttr(Data, 'token', '312312'); // returns 1
findWithAttr(Data, 'id_list', '10'); // returns -1
The function returns -1 when not found, so it follows the same construct as Array.prototype.indexOf().
If you're having issues with Internet Explorer, you could use the map() function which is supported from 9.0 onward:
var index = Data.map(item => item.name).indexOf("Nick");
var index = Data.findIndex(item => item.name == "John")
Which is a simplified version of:
var index = Data.findIndex(function(item){ return item.name == "John"})
From mozilla.org:
The findIndex() method returns the index of the first element in the array that satisfies the provided testing function. Otherwise -1 is returned.
Only way known to me is to loop through all array:
var index = -1;
for(var i=0; i<Data.length; i++)
if(Data[i].name === "John") {
index = i;
break;
}
Or case insensitive:
var index = -1;
for(var i=0; i<Data.length; i++)
if(Data[i].name.toLowerCase() === "john") {
index = i;
break;
}
On result variable index contain index of object or -1 if not found.
A prototypical way
(function(){
if (!Array.prototype.indexOfPropertyValue){
Array.prototype.indexOfPropertyValue = function(prop, value){
for (var index = 0; index < this.length; index++){
if (this[index][prop]){
if (this[index][prop] == value){
return index;
}
}
}
return -1;
}
}
})();
// Usage:
var Data = [
{id_list:1, name:'Nick', token:'312312'}, {id_list:2, name:'John', token:'123123'}];
Data.indexOfPropertyValue('name', 'John'); // Returns 1 (index of array);
Data.indexOfPropertyValue('name', 'Invalid name') // Returns -1 (no result);
var indexOfArray = Data.indexOfPropertyValue('name', 'John');
Data[indexOfArray] // Returns the desired object.
you can use filter method
const filteredData = data.filter(e => e.name !== 'john');
Just go through your array and find the position:
var i = 0;
for(var item in Data) {
if(Data[item].name == 'John')
break;
i++;
}
alert(i);
let indexOf = -1;
let theProperty = "value"
let searchFor = "something";
theArray.every(function (element, index) {
if (element[theProperty] === searchFor) {
indexOf = index;
return false;
}
return true;
});
collection.findIndex(item => item.value === 'smth') !== -1
You can use Array.sort using a custom function as a parameter to define your sorting mechanism.
In your example, it would give:
var Data = [
{id_list:1, name:'Nick',token:'312312'},{id_list:2,name:'John',token:'123123'}
]
Data.sort(function(a, b){
return a.name < b.name ? -1 : a.name > b.name ? 1 : 0;
});
alert("First name is : " + Data[0].name); // alerts 'John'
alert("Second name is : " + Data[1].name); // alerts 'Nick'
The sort function must return either -1 if a should come before b, 1 if a should come after b and 0 if both are equal. It's up to you to define the right logic in your sorting function to sort the array.
Missed the last part of your question where you want to know the index. You would have to loop through the array to find that as others have said.
This might be useful:
function showProps(obj, objName) {
var result = "";
for (var i in obj)
result += objName + "." + i + " = " + obj[i] + "\n";
return result;
}
I copied this from Working with objects.
Use a small workaround:
Create a new array with names as indexes. After that all searches will use indexes. So, only one loop. After that you don't need to loop through all elements!
var Data = [
{id_list:1, name:'Nick',token:'312312'},{id_list:2,name:'John',token:'123123'}
]
var searchArr = []
Data.forEach(function(one){
searchArr[one.name]=one;
})
console.log(searchArr['Nick'])
http://jsbin.com/xibala/1/edit
Live example.
I extended Chris Pickett's answer, because in my case I needed to search deeper than one attribute level:
function findWithAttr(array, attr, value) {
if (attr.indexOf('.') >= 0) {
var split = attr.split('.');
var attr1 = split[0];
var attr2 = split[1];
for(var i = 0; i < array.length; i += 1) {
if(array[i][attr1][attr2] === value) {
return i;
}
}
} else {
for(var i = 0; i < array.length; i += 1) {
if(array[i][attr] === value) {
return i;
}
}
};
};
You can pass 'attr1.attr2' into the function.
Use this:
Data.indexOf(_.find(Data, function(element) {
return element.name === 'John';
}));
It is assuming you are using Lodash or Underscore.js.
var fields = {
teste:
{
Acess:
{
Edit: true,
View: false
}
},
teste1:
{
Acess:
{
Edit: false,
View: false
}
}
};
console.log(find(fields,'teste'));
function find(fields,field) {
for(key in fields) {
if(key == field) {
return true;
}
}
return false;
}
If you have one Object with multiple objects inside, if you want know if some object are include on Master object, just use find(MasterObject, 'Object to Search'). This function will return the response if it exists or not (TRUE or FALSE). I hope to help with this - can see the example on JSFiddle.
If you want to get the value of the property token then you can also try this:
let data=[
{ id_list: 1, name: 'Nick', token: '312312' },
{ id_list: 2, name: 'John', token: '123123' },
]
let resultingToken = data[_.findKey(data,['name','John'])].token
where _.findKey is a Lodash function.
You can use findIndex in Lodash library.
Example:
var users = [
{ 'user': 'barney', 'active': false },
{ 'user': 'fred', 'active': false },
{ 'user': 'pebbles', 'active': true }
];
_.findIndex(users, function(o) { return o.user == 'barney'; });
// => 0
// The `_.matches` iteratee shorthand.
_.findIndex(users, { 'user': 'fred', 'active': false });
// => 1
// The `_.matchesProperty` iteratee shorthand.
_.findIndex(users, ['active', false]);
// => 0
// The `_.property` iteratee shorthand.
_.findIndex(users, 'active');
// => 2
Alternatively to German Attanasio Ruiz's answer, you can eliminate the second loop by using Array.reduce() instead of Array.map();
var Data = [
{ name: 'hypno7oad' }
]
var indexOfTarget = Data.reduce(function (indexOfTarget, element, currentIndex) {
return (element.name === 'hypno7oad') ? currentIndex : indexOfTarget;
}, -1);
Maybe the Object.keys, Object.entries, and Object.values methods might help.
Using Underscore.js:
var index = _.indexOf(_.pluck(item , 'name'), 'Nick');
I have the following array
var countries = {};
countries.results = [
{id:'AF',name:'Afghanistan'},
{id:'AL',name:'Albania'},
{id:'DZ',name:'Algeria'}
];
How can I remove an item from this array using its name or id ?
Thank you
Created a handy function for this..
function findAndRemove(array, property, value) {
array.forEach(function(result, index) {
if(result[property] === value) {
//Remove from array
array.splice(index, 1);
}
});
}
//Checks countries.result for an object with a property of 'id' whose value is 'AF'
//Then removes it ;p
findAndRemove(countries.results, 'id', 'AF');
Array.prototype.removeValue = function(name, value){
var array = $.map(this, function(v,i){
return v[name] === value ? null : v;
});
this.length = 0; //clear original array
this.push.apply(this, array); //push all elements except the one we want to delete
}
countries.results.removeValue('name', 'Albania');
Try this:
var COUNTRY_ID = 'AL';
countries.results =
countries.results.filter(function(el){ return el.id != COUNTRY_ID; });
Try this.(IE8+)
//Define function
function removeJsonAttrs(json,attrs){
return JSON.parse(JSON.stringify(json,function(k,v){
return attrs.indexOf(k)!==-1 ? undefined: v;
}));}
//use object
var countries = {};
countries.results = [
{id:'AF',name:'Afghanistan'},
{id:'AL',name:'Albania'},
{id:'DZ',name:'Algeria'}
];
countries = removeJsonAttrs(countries,["name"]);
//use array
var arr = [
{id:'AF',name:'Afghanistan'},
{id:'AL',name:'Albania'},
{id:'DZ',name:'Algeria'}
];
arr = removeJsonAttrs(arr,["name"]);
You can delete by 1 or more properties:
//Delets an json object from array by given object properties.
//Exp. someJasonCollection.deleteWhereMatches({ l: 1039, v: '3' }); ->
//removes all items with property l=1039 and property v='3'.
Array.prototype.deleteWhereMatches = function (matchObj) {
var indexes = this.findIndexes(matchObj).sort(function (a, b) { return b > a; });
var deleted = 0;
for (var i = 0, count = indexes.length; i < count; i++) {
this.splice(indexes[i], 1);
deleted++;
}
return deleted;
}
you can use delete operator to delete property by it's name
delete objectExpression.property
or iterate through the object and find the value you need and delete it:
for(prop in Obj){
if(Obj.hasOwnProperty(prop)){
if(Obj[prop] === 'myValue'){
delete Obj[prop];
}
}
}
This that only requires javascript and appears a little more readable than other answers.
(I assume when you write 'value' you mean 'id')
//your code
var countries = {};
countries.results = [
{id:'AF',name:'Afghanistan'},
{id:'AL',name:'Albania'},
{id:'DZ',name:'Algeria'}
];
// solution:
//function to remove a value from the json array
function removeItem(obj, prop, val) {
var c, found=false;
for(c in obj) {
if(obj[c][prop] == val) {
found=true;
break;
}
}
if(found){
delete obj[c];
}
}
//example: call the 'remove' function to remove an item by id.
removeItem(countries.results,'id','AF');
//example2: call the 'remove' function to remove an item by name.
removeItem(countries.results,'name','Albania');
// print our result to console to check it works !
for(c in countries.results) {
console.log(countries.results[c].id);
}
it worked for me..
countries.results= $.grep(countries.results, function (e) {
if(e.id!= currentID) {
return true;
}
});
You can do it with _.pullAllBy.
var countries = {};
countries.results = [
{id:'AF',name:'Afghanistan'},
{id:'AL',name:'Albania'},
{id:'DZ',name:'Algeria'}
];
// Remove element by id
_.pullAllBy(countries.results , [{ 'id': 'AL' }], 'id');
// Remove element by name
// _.pullAllBy(countries.results , [{ 'name': 'Albania' }], 'name');
console.log(countries);
.as-console-wrapper {
max-height: 100% !important;
top: 0;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>
Maybe this is helpful, too.
for (var i = countries.length - 1; i--;) {
if (countries[i]['id'] === 'AF' || countries[i]['name'] === 'Algeria'{
countries.splice(i, 1);
}
}
The accepted answer is problematic as it attaches a function to the Array prototype. That function will show up whenever you run thru the array using a for loop:
for (var key in yourArray) {
console.log(yourArray[key]);
}
One of the values that will show up will be the function. The only acceptable way to extend base prototypes (although it is generally discouraged as it pollutes the global space) is to use the .defineProperty method:
Object.defineProperty(Object.prototype, "removeValue", {
value: function (val) {
for (var i = 0; i < this.length; i++) {
if (this[i] === val) {
this.splice(i, 1);
i--;
}
}
return this;
},
writable: true,
configurable: true,
enumerable: false
});