My code:
rbx.getPlayers(539310, 1).promise.then(players => {
console.log(players)
for (var list in players.players) {
console.log(list)
var key = Object.Key(list)
console.log(Key)
}
})
What it outputs:
{ total: 9,
players:
{ AgentJay400: 65910635,
MatthewHAndreas: 49787909,
coolguysocoolroblox: 165524669,
CAMPER5155: 45422370,
Mavnkei: 69082588,
kaankerem123: 92305180,
egehan432: 120777218,
panpanaber54: 31962303,
IXTactical_CactusXI: 17451343 } }
AgentJay400
MatthewHAndreas
coolguysocoolroblox
CAMPER5155
Mavnkei
kaankerem123
egehan432
panpanaber54
IXTactical_CactusXI
Problem:
I need the number values of each user (So {AgentJay4000: 65910635} I would want the 65910635) Node.js does not seem to have Object.keys so... I have no clue how to get the number...
Node should definitely have Object.keys. If your version doesn't you should update node. When you call Object.keys you get an array in return, so you can do awesome array things like map, reduce, forEach:
Object.keys(players.players).forEach(function(key) {
console.log(key, players.players[key])
})
If you just want the number values, then map it:
Object.keys(players.players).map(function(key) {
return players.players[key]
})
Now you have an array of the numbers only.
Try like this.You can access your object value using . operator.
Suppose you have an object:
var obj={
key1:value1,
key2:value2
}
Then access values like obj.key1 or obj['key1'].
to get all the values.Use Object.values(obj);
var obj = { total: 9,
players:
{ AgentJay400: 65910635,
MatthewHAndreas: 49787909,
coolguysocoolroblox: 165524669,
CAMPER5155: 45422370,
Mavnkei: 69082588,
kaankerem123: 92305180,
egehan432: 120777218,
panpanaber54: 31962303,
IXTactical_CactusXI: 17451343 } };
var players = obj.players;
var number_values = Object.values(players);
console.log(number_values );
You can output the keys and their associated numbers by doing the following:
rbx.getPlayers(539310, 1).promise.then(players => {
console.log(players)
for (var key in players.players) {
console.log(key, ':', players.players[key])
}
})
To demonstrate how Object.keys works an alternative method of accessing the players - this does the same as the above.
rbx.getPlayers(539310, 1).promise.then(players => {
var keys = Object.keys(players.players);
for (var i = 0; i < keys.length; i++) {
let key = keys[i];
let player = players.players[key];
console.log(key, ':', players.players[key])
}
});
The mistakes you made in your attempt were you were attempting to access Object.key which was a typo for Object.keys and attempting to obtain a list of keys from a string (as a loop such as for(var key in obj) will set key to each key in obj and all object keys are strings).
Here is my functions:
map:
function () {
// initialize KEY
// initialize INDEX (0..65536)
// initialize VALUE
var arr = [];
arr[INDEX] = { val: VALUE, count: 1 };
emit(KEY, { arr: arr });
}
reduce:
function (key, values) {
var result = { arr: [] };
for (var i = 0; i < values.length; i++) {
values[i].arr.forEach(function (item, i) {
if (result.arr.hasOwnProperty(i)) {
result.arr[i].val += item.val;
result.arr[i].count += item.count ;
} else {
result.arr[i] = item;
}
});
}
As you can see, I'm trying to send associative array from map to reduce. But when I try to enumerate values of array values[i].arr.forEach I get listing 0..max_index. So, every reduce I have to enumerate a lot of undefined elements.
When I try to enumerate values of array (arr) at map I get expected result (only defined elements).
Actually, I don't sure that associative array is best solution for my task. But I can't find faster way to find element by id.
Could you please answer the questions:
Why differences of array processing at map and
reduce?
What data structure I should use (or how I should use my array) to optimize my current solution?
I decided to use object:
var arr = {};
arr[INDEX] = { val: VALUE, count: 1 };
It is works with for .. in as expected.
I have this object:
key = {
spawn:{type:1,img:app.assets.get('assets/spawn.svg')},
wall:{type:2,img:app.assets.get('assets/wall.svg')},
grass:{type:3,img:app.assets.get('assets/grass.svg')},
spike:{type:4,img:app.assets.get('assets/spike.svg')},
ground:{type:5,img:app.assets.get('assets/ground.svg')}
};
And I have an array with only types and I need to add the given image to it, the array looks something like this:
[{type:1,image:null},{type:3,image:null},{type:2,image:null},{type:2,image:null},{type:5,image:null}]
Basically I want to loop the array, find the type in the key object and get the given image and save it into the array.
Is there any simple way to do this?
One thing that stands out here for me is the line
...get the given image and save it into the array
I'm assuming this means the original array. I think a better approach would be to map the appropriate keys and values to a new array but I've assumed, for this example, that it's a requirement.
In an attempt to keep the solution as terse as possible and the request for a lodash solution:
_.each(key, function(prop){
_.each(_.filter(types, { type: prop.type }), function(type) { type.image = prop.img });
});
Given the object of keys and an array of objects like so:
var key = {
spawn:{type:1,img:app.assets.get('assets/spawn.svg')},
wall:{type:2,img:app.assets.get('assets/wall.svg')},
grass:{type:3,img:app.assets.get('assets/grass.svg')},
spike:{type:4,img:app.assets.get('assets/spike.svg')},
ground:{type:5,img:app.assets.get('assets/ground.svg')}
};
var arr = [{type:1,image:null},{type:3,image:null},{type:2,image:null},{type:2,image:null},{type:5,image:null}];
We can first create an array of the properties in the object key to make iterating it simpler.
Then loop over the array arr, and upon each member, check with a some loop which image belongs to the member by its type (some returning on the first true and ending the loop).
You can change the forEach to a map (and assign the returned new array to arr or a new variable) if you want the loop to be without side-effects, and not to mutate the original array.
var keyTypes = Object.keys(key);
arr.forEach(function (item) {
keyTypes.some(function (keyType) {
if (key[keyType].type === item.type) {
item.image = key[keyType].img;
return true;
}
return false;
});
});
The smarter thing would be to change the object of the imagetypes so that you could use the type as the accessing property, or create another object for that (as pointed out in another answer).
I'm not sure if this solution is modern, but it does not use any loops or recursion.
object = {
spawn: {type:1, img:app.assets.get('assets/spawn.svg')},
wall: {type:2, img:app.assets.get('assets/wall.svg')},
grass: {type:3, img:app.assets.get('assets/grass.svg')},
spike: {type:4, img:app.assets.get('assets/spike.svg')},
ground: {type:5, img:app.assets.get('assets/ground.svg')}
};
arr = [
{type:1, image:null},
{type:3, image:null},
{type:2, image:null},
{type:2, image:null},
{type:5, image:null}
];
var typeImages = {};
Object.getOwnPropertyNames(object).forEach(function(value){
typeImages[object[value].type] = object[value].img;
});
arr = arr.map(function(value){
return {
type: value.type,
image: typeImages[value.type]
};
});
var key = {
spawn:{type:1,img:app.assets.get('assets/spawn.svg')},
wall:{type:2,img:app.assets.get('assets/wall.svg')},
grass:{type:3,img:app.assets.get('assets/grass.svg')},
spike:{type:4,img:app.assets.get('assets/spike.svg')},
ground:{type:5,img:app.assets.get('assets/ground.svg')}
};
var typesArray = [{type:1,image:null},{type:3,image:null},{type:2,image:null},{type:2,image:null},{type:5,image:null}];
for(var i = 0, j = typesArray.length; i < j; i++)
{
typesArray[i].image = getKeyObjectFromType(typesArray[i].type).img;
}
function getKeyObjectFromType(type)
{
for(var k in key)
{
if(key[k].type == type)
{
return key[k];
}
}
return {};
}
for (var i = 0; i < typesArray.length; i++) {
for (prop in key) {
if (key[prop].type === typesArray[i].type) {
typesArray[i].image = key[prop].img;
}
}
}
It loops through the array ("typesArray"), and for each array item, it go through all the objects in key looking for the one with the same "type". When it finds it, it takes that key object's "img" and saves into the array.
Using lodash (https://lodash.com/):
var key = {
spawn:{type:1,img:app.assets.get('assets/spawn.svg')},
wall:{type:2,img:app.assets.get('assets/wall.svg')},
grass:{type:3,img:app.assets.get('assets/grass.svg')},
spike:{type:4,img:app.assets.get('assets/spike.svg')},
ground:{type:5,img:app.assets.get('assets/ground.svg')}
};
var initialList = [{type:1,image:null},{type:3,image:null},{type:2,image:null},{type:2,image:null},{type:5,image:null}];
var updatedList = _.transform(initialList, function(result, item) {
item.image = _.find(key, _.matchesProperty('type', item.type)).img;
result.push(item);
});
This will go over every item in the initialList, find the object that matched their type property in key and put it in the image property.
The end result will be in updatedList
I have built an object in PHP, used JSON_encode function and send it as a JSON string to my JS script via ajax. Then I convert it back to an object. The problem I am having is that I wanted to keep the object in the order that it was originally created in. Please see this picture of what the object looks like once I get it into JS:
When I created the object, it was sorted by the customer field alphabetically. The customer name starting with A would come first, B second, etc. As you can see, now, the first element of the object as customer starting with S. It looks like somehow it got automatically sorted by the key of the top-level object, which is an integer, so I understand why this happened.
So i want to do is re-sort this object so that all the sub-objects are sorted by the customer field alphabetically. Is this possible? If so, how do I do it?
Thanks!
I've changed Fabricio Matée answer to become more flexible and return the sorted object.
function alphabetical_sort_object_of_objects(data, attr) {
var arr = [];
for (var prop in data) {
if (data.hasOwnProperty(prop)) {
var obj = {};
obj[prop] = data[prop];
obj.tempSortName = data[prop][attr].toLowerCase();
arr.push(obj);
}
}
arr.sort(function(a, b) {
var at = a.tempSortName,
bt = b.tempSortName;
return at > bt ? 1 : ( at < bt ? -1 : 0 );
});
var result = [];
for (var i=0, l=arr.length; i<l; i++) {
var obj = arr[i];
delete obj.tempSortName;
for (var prop in obj) {
if (obj.hasOwnProperty(prop)) {
var id = prop;
}
}
var item = obj[id];
result.push(item);
}
return result;
}
Then just call the function like this
your_object = alphabetical_sort_object_of_objects(your_object, 'attribute_to_sort');
It's probably the difference between a JavaScript Object and a JavaScript Array. Objects are more like hash tables, where the keys aren't sorted in any particular order, whereas Arrays are linear collections of values.
In your back end, make sure you're encoding an array, rather than an object. Check the final encoded JSON, and if your collection of objects is surrounded by {} instead of [], it's being encoded as an object instead of an array.
You may run into a problem since it looks like you're trying to access the objects by an ID number, and that's the index you want those objects to occupy in the final array, which presents another problem, because you probably don't want an array with 40,000 entries when you're only storing a small amount of values.
If you just want to iterate through the objects, you should make sure you're encoding an array instead of an object. If you want to access the objects by specific ID, you'll probably have to sort the objects client-side (i.e. have the object from the JSON response, and then create another array and sort those objects into it, so you can have the sorted objects and still be able to access them by id).
You can find efficient sorting algorithms (or use the one below from ELCas) easily via Google.
Here's a generic iteration function which pushes all objects into an array and sorts them by their customer property in a case-insensitive manner, then iterates over the sorted array:
function iterate(data) {
var arr = [];
for (var prop in data) {
if (data.hasOwnProperty(prop)) {
var obj = {};
obj[prop] = data[prop];
obj.tempSortName = data[prop].customer.toLowerCase();
arr.push(obj);
}
}
arr.sort(function(a, b) {
var at = a.tempSortName,
bt = b.tempSortName;
return at > bt ? 1 : ( at < bt ? -1 : 0 );
});
for (var i = 0, l = arr.length; i < l; i++) {
var obj = arr[i];
delete obj.tempSortName;
console.log(obj);
for (var prop in obj) {
if (obj.hasOwnProperty(prop)) {
var id = prop; //gets the obj "index" (id?)
}
}
console.log(id);
var item = obj[id];
console.log(item.customer);
//do stuff with item
}
}
Fiddle
sortObject(object){
if(typeof object === 'object'){
if(object instanceof Date){
return object;
}
if(object instanceof Array){
return object.map(element => this.sortObject(element));
} else {
return Object.keys(object).sort().reduce((result, key) => {
if(object[key] && object[key] !== null) {
result[key] = this.sortObject(object[key]);
}
return result;
}, {});
}
}
return object;
}
I have a JSON object with the following format:
{
items:{
nestedObj:{
position:3
},
nestedObj2:{
position:1
},
nestedObj3:{
position:2,
items:{
dblNestedObj:{
position:2
},
dblNestedObj2:{
position:3
},
dblNestedObj3:{
position:1
}
}
}
}
}
I am attempting to sort each level of nested object by their position attribute. I can recursively iterate the object, but I don't know where to start for sorting it...
Unfortunately it's not quite so easy to use the sort method as it would if you had an array. So let's build an array:
var tmp = [], x;
for( x in obj.items) { // assuming your main object is called obj
tmp.push([x,obj.items[x].position]);
// here we add a pair to the array, holding the key and the value
}
// now we can use sort()
tmp.sort(function(a,b) {return a[1]-b[1];}); // sort by the value
// and now apply the sort order to the object
var neworder = {}, l = tmp.length, i;
for( i=0; i<l; i++) neworder[tmp[i][0]] = obj.items[tmp[i][0]];
obj.items = neworder;